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Assuming a future population of 9.5 billion people, India would have the greatest population, more than 600 million, exposed at 2.7°C global warming. At 1.5°C, this figure would be far lower, at about 90 million.

The Los Angeles winter wildfires have sent shockwaves across the world, so far claiming 24 lives and displacing over a lakh people. Unfavourable weather conditions continue to fuel a fresh round of forest fires for the seventh consecutive day since January 7. Forecasters are afraid there will be no respite in the coming days, as winds are again likely to pick up pace.

The blaze gutted around 12000 structures, and the damage and economic loss are estimated at $135 billion to $150 billion. Reportedly, the Palisades, Eaton, Kenneth and Hurst fires have consumed about 62 square miles (160 square kilometers).

The devastating wildfires sweeping through Los Angeles and surrounding areas were supercharged by global warming. The incident has highlighted the severe impacts of climate change and underscored the urgency of taking action before the situation spirals beyond human control.

“These wildfires are a reminder of how human-driven climate change amplifies extreme weather events. Many people have been affected, including Hollywood stars, demonstrating that climate change spares no one. This disaster serves as a stark reminder that we must collectively demand immediate action to mitigate these escalating risks and safeguard our shared future,” said Davide Faranda, Researcher, IPSL-CNRS (Centre for Scientific Research (CNRS), France.

Climate change’s significant contribution

The catastrophic wildfires are being driven by extraordinary meteorological conditions intensified by climate change, according to scientists from the ClimaMeter project who did a rapid study on the fire incident. The report noted that meteorological conditions similar to those triggering the Los Angeles wildfires are now up to 5°C (9ºF) warmer, 3 mm/day (up to 15%) drier, and up to 5 km/h (20%) windier compared to the past. Human-driven climate change was identified as the main driver of the strengthened winds, higher temperatures, and drier conditions, with natural climate variability playing a minor role.

Much of Southern California had almost no rainfall since July 2024, despite being halfway into the normal rainy season – the second-driest period in 150 years. Climate change is making it less likely to rain in late fall and early winter when the hot, dry, Santa Ana winds peak. The Santa Ana winds typically originate from cool and dry high-pressure masses in the Great Basin. The dry and powerful winds blow down the mountains towards the Pacific Coast, with gusts that can reach hurricane strength.

California also had its hottest June and July and the second hottest October, with many of the hot days scientifically linked to climate change. This heat and lack of rainfall left the vegetation tinder dry when the Santa Ana winds started.

“Climate change is playing a role in the increase of fire weather in the West, where more days of dry, warm, windy weather are amplifying the risks of wildfires spreading rapidly. As our climate warms, the chances of intense, fast-growing fires like the ones Californians are facing today will keep rising,” said Kaitlyn Trudeau, Senior Research Associate for Climate Science, Climate Central.

How wildfires unfolded

Terming it a rare event, experts cite that these fires were fuelled by different meteorological and hydrological conditions: very low humidity, dry conditions (with very little moisture over the past several months), and Santa Ana winds, exceeding 130-160 km/h in some places.

The Surface Pressure Anomalies show a low-pressure area (cut-off low) over Southern California with values up to -10 hPa. According to the analysis based on ERA5 data, temperature anomalies displayed conditions up to +5°C warmer in the area affected by the fire. Precipitation data showed dry conditions. Wind speed Data indicated strong winds blowing from California Mountain ranges to the Pacific Ocean. These winds are triggered by cut-off lows over California.

Researchers carried out the analysis comparing similar low-pressure systems during the late 20th century (1950–1986) with those in recent decades (1987–2023), a period when climate change impacts have become more evident.

How global warming exacerbated the situation

Scientists have termed the ongoing wildfire situation as ‘Fire Weather’ which refers to meteorological conditions that promote the spread of wildfires. Fire weather creates ideal conditions for wildfires to ignite and spread. As fire weather becomes more frequent, there are more days when extreme conditions can escalate small fires into large ones or accelerate the growth of major wildfires, as seen in the ongoing blaze. Three conditions are fundamental to fire weather: temperature, relative humidity, and wind.

Hotter temperatures have a direct influence on fire behaviour, heating the fuels and making them more likely to ignite. Warmer nighttime temperatures decrease the overnight relative humidity that could have helped firefighters gain control over wildfires. The Temperature Changes show that similar events produce temperatures in the present climate up to 5 °C warmer than what they would have been in the past.

Humidity: When relative humidity levels are very low, the air pulls moisture from the land, leaving vegetation dry and prone to burning. Precipitation Changes show that present events are dryer (up to 15%) than the past.

Wind supplies oxygen to a fire, causing it to burn more rapidly. Wind increases evaporation, drying out the land. Wind also carries embers, which helps fires spread. Windspeed Changes indicated up to 5 km/h windier conditions over the areas interested by the fires.

Another Climate Central’s analysis indicated that decreasing relative humidity has been a major factor in boosting annual fire weather days for many locations across the U.S. Wildfire seasons are lengthening and intensifying, particularly in the West. Many parts of the East have seen smaller but impactful increases in fire weather days. Much of the West and East are experiencing the greatest increase in fire weather during spring months. The Southwest is also seeing a boost in fire weather during summer.

While fires are a natural component of ecosystems, climate change is influencing the frequency and intensity of extreme weather events, which in turn affects the occurrence and severity of wildfires. Human-driven climate change has notably expanded the areas impacted by wildfires in some regions and extended the duration of fire weather seasons.

LA Fires California wildfires Climate Change Global Warming

A new study revealed that emerging economies would face challenges in improving their living standards while stabilising their carbon dioxide (CO2) emissions in a bid to meet net-zero goals.

The 28th Conference of Parties (COP28) to the United Nations Convention on Climate Change (UNFCCC) recently culminated with nearly 200 nations pledging to combat the escalating climate crisis by significantly slashing fossil fuel-based emissions and transitioning towards cleaner energy sources.

However, the circumstances vary from country to country, especially for low- and middle-income countries, which are experiencing rapid population expansion. In such a given scenario, economic growth may encounter challenges in achieving decent living standards (DLS) in emerging economies. In fact, the research puts special emphasis on emerging Asian and African economies that would require more additional CO2 emissions in achieving DLS.

Africa, Asia and Latin America struggle to provide basic material requirements like food, clothing, housing, sanitation, health, education, water, electricity, mobility to their ever expanding population. The living standard in India is lower than the average level for global emerging economies with 63.5% of the population not having access to safe sanitation. More than half of the population in the majority of the African countries do not have access to safe drinking water.

Challenges in improving living standards while stabilising CO2 emissions

Although they consist of more than 80% of the global population, developing nations currently account for only 20% of global emissions due to low levels of resource consumption and poor living standards. Essential energy is required to meet the basic needs of everyone.

An improvement in living standards in these emerging economies will therefore shoot up energy demands. Chiefly reliant on fossil fuels based energy sources with outdated energy infrastructures, economic development in these countries will thus be accompanied by an increase in CO2 emissions. For example, coal power generation is the main power source in India, accounting for about 70% of the total power generation capacity. This reliance on coal is concerning, considering the high emission intensity of coal power plants.

Achievement of decent standard of living (DLS) in emerging economies will result in 8.6 Gt of additional CO2 emissions above the 2019 level. This falls well within the global climate targets, but can overshoot domestic emission reduction commitments, finds this study. 62 emerging economies are expected to emit more CO2 than the emissions value pledged in their national reduction commitments to achieve DLS for their population.

For example, achievement of DLS for all in India may result in an increase of CO2 emissions by 315.5% (2.5 Gt) as compared to 2019, far surpassing the domestic targets. Africa may face a threefold increase in CO2 emissions for achieving DLS with mobility and electricity being the main contributors to emissions in both Asia and Africa.

Investment in renewable energy is the key

The analysis recommends greater investment in renewable energy with emphasis on green transportation and green power generation as the main pathway to reducing emissions while achieving decent standards of living in the developing nations. This resonates with the commitment of countries at COP28 to triple renewable energy by 2030.

How emerging economies strive to balance their development needs with energy transition and emission reduction targets will be more evident as they revise their Nationally Determined Contributions to emission reduction by 2025.

Climate Change Carbon Dioxide Emissions Developing nations Global Warming COP28

On February 7, television channels and mobile devices were inundated with dramatic images of a flash flood caused by a possible glacier collapse in the Chamoli district of Uttarakhand. A swollen Dhauli Ganga river gave way, causing massive destruction, killing 37 people (at the time of publishing, with 168 people still missing) and washing away the under-construction Tapovan-Vishnugad hydropower project. Rescue operations continue to search for missing people, who had mere seconds to run to safety. But was this just another glacier break considered commonplace in high mountainous regions or were we witness to the wrath of climate change, as suggested by many experts?

Trigger theories

Scientists are currently piecing together the trigger for the flash flood. Preliminary evidence and satellite images suggest that the sudden increase in the river’s discharge was caused by an avalanche following heavy snowfall near the feeding glacier in the Nandadevi mountain range at an elevation of around 5,000 metres. The mass movement of rock and ice, in turn, caused a glacial overhang near the snout (called a hanging glacier) to collapse into the river around 2,000 metres below, say experts studying the incident.

“Our initial assessments and satellite images suggest the flash flood was triggered by ice-rock fall in the higher altitudes of the range. Currently, it looks like a hanging glacier broke off near the snout of the main glacier and had a free fall into the valley, causing the surge in flow. However, questions regarding the increased volume of water still remain,” explains Mohd Farooq Azam, assistant professor of Glaciology and Hydrology at IIT Indore. The most probable explanation for this, adds Azam, is an accumulation of melt water from heavy snowfall in January and early February that had collected in a small pond, which was breached as the rock and ice from the hanging glacier crashed into the valley.

A separate analysis conducted at IISc indicates the release of water from an underground glacial lake led to the flash flood. The team based its conclusion on images that suggest a 25 hectare depression in the bedrock near glacial ice in northern Nanda Devi, which is part of the Garhwal Himalayas in Chamoli district. New satellite imagery, however, also points to the possibility that the flash flood was a result of fresh snow falling off the mountain, resulting in an avalanche that is estimated to have released 3-4 million cubic metres of water in the surrounding rivers.

Latest images show a new lake forming due to accumulated debris in the river from Sunday’s incident, setting off fears of the possibility of a second surge in the river.

Is there a climate change link?

While such occurrences are fairly commonplace and natural in high mountain environments, experts feel the imprints of climate change are clear. “Such breakages in hanging glaciers happen a lot in high mountains as overhangs snap periodically under heavy ice loads. However, it is also clear now that the warmer winters being experienced in recent years have negatively impacted the stability of such formations. This could have been an added factor in the recent incident,” says Azam.

The Himalayas still represent one of the largest gaps in knowledge when it comes to studying climate change and its implications. However, increased research interest over the past decade has slowly revealed worrying changes in the region, which has been experiencing above average rates of warming over the past 50 years. The largest and most comprehensive assessment yet of the Hindu Kush Himalayas (HKH), published in early 2019 by the International Centre for Integrated Mountain Development (ICIMOD), found that rates of warming in the HKH region were not only higher, but would continue well into the 21^st century even if global warming was limited to 1.5°C. The report also noted that increasing temperature had meant that while extreme cold events were on the decline, extreme warm weather events have become more pronounced. Recent research has not only estimated alarming rates of glacier retreat and reductions in glaciated area in the Himalayan region, it has also revealed rapid fragmentation of glaciers.

The dangers of glacier melt

“With increasing global warming, the upper reaches of the Himalayas are warming faster, leading to more rapid melting of the glaciers. This has resulted in an increasing number of glacier lakes, which are formed by water melting from the ice caps and accumulating at the mouth or snout of the glacier. These lakes also become reservoirs of ice and moraine debris. With an increase in this phenomenon, the breach of glacier lakes poses a severe threat to the communities living downstream,” says AP Dimri, a professor at the School of Environmental Science at Jawaharlal Nehru University.

Glacier melt is a complex process that culminates from not only surface temperatures and meteorology, but also topography, debris cover, depth of ice, bedrock slopes, just to name a few factors. Worryingly, smaller glaciers melt faster than larger ones. The fragmentation of the Himalaya’s glaciated sections implies further acceleration of glacier melt.

Further complicating matters, the loss in glacier ice mass has translated to rapid proliferation of glacier lakes formed from accumulating melt water held back by naturally formed rock and ice walls. According to remote sensing data, there are over 25,600 glacial lakes formed due to meltwater from glaciers across the HKH, covering an area of 1,414 sqkm. Research on these lake formations, especially following the 2013 Kedarnath tragedy, have increasingly warned of the progressively worsening risks posed by the growing number of lakes. The high seismicity of the Himalayan region amplifies the risks of glacial lake dam walls breaching and downstream flash flooding.

“There are currently no conclusive causal links between Sunday’s flash flood and the construction downstream. However, it does indicate heightened risks for such projects, which requires a holistic rethink of our planning approach. Big glacial lakes pose a major threat, but it is highly probable that relatively smaller incidents triggered by glacial instability will also increase in the future with potentially devastating consequences,” expounds Azam. 

Backing a fragile nexus

The Himalayan glacier network is responsible for feeding massive perennial river systems in South Asia, which include the Ganga, Brahmaputra and Indus river basins. Apart from the water flowing through these systems, the glaciers represent huge energy generation potential. According to official assessments published by the ministry of power, India’s Himalayan states carry over 104 GW of hydro power potential, of which only about 20 GW have been currently tapped. This massive potential has meant that despite the expanding recognition of the dangers posed by the volatility in the Himalayan ecosystem, India has continued to grow the number of high altitude hydropower projects.

The bad reputation garnered by large dams for mass displacement and pronounced environmental impacts led to the drying up of international finance for such projects in the 1990s. This, accompanied by the privatisation of hydro power in India, led to a pivot in India’s energy planning strategy.

While the 1995 Mega Power Policy paved the way for private investment hydro power, the 50,000 MW Hydro Initiative launched in 2003 started the image makeover of hydro power as a sustainable source of renewable energy. Rather than large earth dams that required enormous amounts of capital, the government decided to tap the energy potential through smaller projects situated higher up in the mountains. In the two decades since, small hydro projects, fed through tunnels bored into mountain ranges have cropped up across all of India’s Himalayan states. With private investments in sight, India’s policy framework for hydropower promoted progressive deregulation of the renewable energy market, minimal state interventions, and relaxations in clearance procedures. Importantly, state governments were given the power to allot and commission projects independently.

Currently, more than 20 GW of hydro power split over 65 projects are in operation across Himalayan states, with Himachal Pradesh representing nearly half of this capacity. A further 29 projects, with a capacity of 9.7 GW, are currently being constructed despite rising evidence of the risks posed by land use change in the region.

The Kedarnath aftermath

Following the devastating 2013 Kedarnath flash floods, the Supreme Court appointed an Expert Appraisal Committee to look into the viability of 24 hydroelectric projects flagged by the Wildlife Institute of India (WII) as having significant impacts on the ecosystems of the Alaknanda and Bhagirathi basins. The committee looked into the 24 projects planned at elevations of more than 2,500 metres and recommended an immediate stoppage to 23 of the projects. The committee further recommended a review of all the under-construction and proposed hydro power projects, which entail tunnelling, formation of a barrage or a reservoir.

Source: CEA Monthly Generation December 2020 update

National Thermal Power Corporation’s (NTPC) Tapovan-Vishnugad hydropower project, situated at an altitude of about 1,700 metres, which was all but washed away in Sunday’s flash flood, exemplifies the current underestimation of risks associated with high altitude development projects. The Tapovan-Vishnugad HPP, which was not planned to handle sudden surges in river flow, was not equipped with any early warning systems. This means there was practically no advance warning of the flood. Similar incidents over the past few years reported from Himachal Pradesh and Sikkim show that the under-preparation and poor planning reflected in Sunday’s incident is chronic rather than exceptional.

According to CarbonCopy’s analysis of hydropower project details updated by the Central Electricity Authority in December 2020, projects with over 15 GW of generating capacity currently operate or are currently being built at a height of over 1,500 metres, making them particularly vulnerable to extreme weather and changes in glacier dynamic further upstream. 

A matter of unbalanced risks

The increasing number of accidents associated with infrastructure development in the Himalayan region has not gone unnoticed by locals directly affected by the projects. Sunday’s disaster in Chamoli might have been the tipping point of public opinion when it comes to high-altitude hydropower projects. Residents from at least two panchayats in Himachal Pradesh’s Lahaul-Spiti district have now raised demands to scrap planned projects in the district. Closer to the site of the latest incident, residents of Pipalkoti in Uttarakhand have intensified their protests against blasting and tunnelling work being done for THDC’s Vishnugad-Pipalkoti hydro electric project. Similar protests by locals in Sikkim and Arunachal Pradesh against planned and under-construction hydro electric projects have been reported over the past few years.

India’s Hydropower Policy of 2008, the directive document for India’s hydropower planning, is replete with concessions and exemptions, which insulate operating entities from most of the risks inherent in the sector. These risks, experts have argued, have been shifted onto the public, while margins of profits are maximised. Guaranteed payments for “design generation” and tariff regimes further nullify any incentive to optimise and upgrade designs more in line with environmental thresholds and projected changes.

Studies looking into India’s hydropower development also point out that joint ventures often used to implement projects “reduce the distance between project regulators and implementers.” This has led to compromises in environmental assessment impacts (EIAs), which often exhibit proof of sanitisation by developers to remove problematic aspects.

“Planning and implementing large engineering projects on himalayan rivers is fraught with great risks. Most scholars of Himalayan rivers have been warning about these risks for decades, but the EIA for these projects withhold or underplay this information so that projects get approved. Given that climate change is such a complex phenomenon and is affecting everything in our environments, development and environmental policies should really not be selecting these options that put people at great risk,” says Manju Menon a senior fellow working on climate policy and environmental justice at the Centre for Policy Research.

Provisions made to attract investments currently have culminated in an unequal balance of the risks associated. This in turn has led to India’s hydro-power fleet being grossly misaligned with not only ecological sustainability of projects, but also their capacity to withstand impacts of environmental changes. This issue of unbalanced risks is not only a problem for the hydropower sector, but extends across infrastructure projects.

What India currently needs is a thorough reassessment of its policy and plan regarding hydropower and other infrastructure development to not only gauge the impact of the project, but also their adaptive capacity. Sustainable, after all, is no longer simply a matter of environment-friendliness in design, but also includes the ability to absorb and insulate against impending changes in the Himalayan region.

India records excess Pre-Monsoon Season 2023, gives heatwave a miss The pre-Monsoon season for the country ended with surplus rainfall to the tune of 12% of the Long Average Period (LPA). All three months (March-May) have recorded excess rainfall countrywide.

Data Source: IMD (Rainfall figures in mm)

While the majority rainfall contribution came from Central India, East and Northeast India was the only pocket to record deficit rainfall. Out of 36 sub-divisions of the country, 17 were large excess during the season, four saw excess rains, and 7 recorded normal rains. Meanwhile, six sub-divisions received deficient rains, while two were large deficient.

Excess rainfall led to below-normal maximum Temperatures observed over Northwest India, giving a miss to heatwave season this year.  West Bengal was the only pocket to see a major heatwave spell from April 11-19. Following are the number of heatwave days observed across the country during the season.

Month-wise performance:

May: The month ended with surplus rainfall for the country to the tune of 10% of its LPA of 61.4 mm. Out of the 36 subdivisions of the country, 24 recorded normal to large excess rainfall, while others were deficient to large deficient.

According to the statistics, Northwest India recorded 67.3 mm of rain during May, the third highest since 1901.  Before this, 1987 had recorded 95 mm, followed by 2021 with 68.2 mm during the month. Meanwhile, East & Northeast India received 111.3 mm of rainfall, the third lowest since 1901. Prior lowest rainfall years for the regions are 1907 with 108.1 mm of rain and 2012 with 109.6 mm.

Temperature Profile: With the above-normal rainfall, India recorded close to normal maximum and minimum average temperatures. The maximum temperature for the month was recorded at 35.03°C and the minimum temperature was 23.92°C, with an anomaly of -0.14°C and -0.40°C, respectively. The maximum temperature was above normal by 4.4°C mainly over most parts of North India and East & Northeast India and coastal parts of India.

Northwest India: Not only the rainfall, but the region also recorded the eighth-lowest average maximum temperature of 33.53°C, which was lower by 2.06°C since 1901. Similarly, the average minimum temperature was the seventh lowest at 20.09°C with an anomaly of -1.37°C during the same period. The mean temperature was also the eighth lowest at 26.81°C with an anomaly of -1.71°C since 1901.

Central India: The average minimum temperature for May was the sixth lowest at 25.20°C with an anomaly of -0.74°C since 1901.

East & Northeast India: In the absence of rains, the average maximum temperature was the eighth highest at 34.33 ºC with an anomaly of 1.30 ºC since 1901.

Heat Wave: Subdued heat wave conditions were observed during May, following similar trends in March and April 2023. Heatwave spells were observed for a span of 2-3 days over a few pockets of the country. The first week (1-8 May) and last week (24-31 May) did not observe heatwave across the country.

Weather Systems: May saw a series of back-to-back eight WDs, which is quite unusual during this time of the year. Passage of these systems led to widespread pre-Monsoon rains and thunderstorms, along with lighting, hail storm, and squally winds, especially over Northwest and Central India. These weather activities kept the maximum temperature below average over the regions.

April: The month also saw above-normal countrywide rainfall by 5% of its LPA. Central India recorded 30 mm of rain, which was the fourth highest since 1901. Meanwhile, East & Northeast India received 63.8 mm of rainfall which was the fifth lowest during the same period.

Out of the 36 subdivisions of the country, 26 recorded normal to large excess rainfall, while others were deficient to large deficient.

Weather systems: April witnessed five active Western disturbances (one in the first week of the month and four in the second half of the month). There was also the persistence of trough/wind discontinuity running from central to Peninsular India. Both weather systems together led to large-scale thunderstorm activities and rainfall, accompanied by lightning and gusty winds over India along with hail storms. Due to such extensive rain/thunderstorm activities and cloudy conditions over most parts of India, large parts of India experienced lower-than-normal day maximum temperatures during these periods.

The absence of weather systems along with south-westerly or southerly winds and moisture convergence from the north Bay of Bengal to the region was the reason behind the subdued rainfall and thunderstorm activities over northeast India in April.

Temperature Profile: The average maximum, average minimum and mean temperature for the country as a whole during April 2023 are 34.19°C, 22.08°C and 28.14°C respectively, against the normal of 33.94°C, 22.15°C and 28.04°C based on the period 1981-2010. Thus, the average maximum temperature is above normal by 0.26°C while the average minimum temperature and mean temperature are normal by -0.07°C and 0.10°C respectively for the country as a whole. The average Maximum temperature was above normal by 4.5°C mainly over most parts of East & Northeast India and coastal parts of South Peninsular India.

Peninsular India: Over South Peninsular India during April, the average maximum temperature is the seventh highest (35.03°C with an anomaly of 0.77°C). 

Heat Wave: During April 2023, there was no heat wave during 1-10 April and 21-30 April due to the occurrence of thunderstorms and rainfall activities, especially over Northwest and West-Central India. During 12-20 April, heat wave condition was observed over West Bengal for 9 days, Bihar – 7 days, Odisha – 5 days, and Coastal Andhra Pradesh-4 days during the period.

Punjab, Haryana, Chandigarh, Delhi, and Uttar Pradesh saw heatwave conditions for 1-3 days, while Konkan & Goa and Jharkhand just saw one day of Heat Wave activity.

March:  March was the best-performing month of the pre-Monsoon season 2023, with 26% surplus countrywide rainfall of its LPA. Out of the 36 subdivisions of the country, 29 recorded normal to large excess rainfall, while others were deficient to large deficient.

According to the statistics, Peninsular India recorded 32.1 mm during the month, the seventh highest since 1901. Similarly, Central India also saw the 11th highest rainfall during the same time period with 23.9 mm of rainfall.

Weather systems: After the hottest February in 123 years on account of the absence of Western Disturbances, March 2023 saw seven WDs formed moving across north and central India. Due to back-to-back WDs, an east-west trough was formed from Rajasthan to eastern India. Another north-south trough was seen running from south Peninsular India to east-central India, which is a semi-permanent feature during the pre-Monsoon season. The country saw widespread rainfall, especially from March 14-22.

Temperature Profile: The average maximum temperature for the country was recorded at 31.37°C, which was above normal by 0.13°C against the normal average of 31.24°C. Similarly, average minimum and mean temperatures were recorded above normal at 19.46 ºC and 25.41 ºC respectively, against the normal of 18.87°C and 25.06°C. However, these above-normal temperatures were the result of hot weather in the first half of the month. Maximum temperatures were below normal departure since March 17 because of thunderstorm activity over many parts of the country.

Heat Wave: No heatwave was recorded during the month.

Hottest February shatters record, India gears up for intense heatwaves aheadIndia witnessed the hottest February since 1901, with average maximum temperature peaking at 29.54°C. This was higher by 1.7°C in comparison to the normal average temperature of 27.8°C. Average minimum temperature for February, 2023 also settled above the normal by 1.3°C and was the fifth highest during the same period.

Region-wise, Northwest and Central India bore the maximum brunt, with both regions making it to the record list of all-time high day maximum temperatures with rank 1 and 2, respectively.

Data courtesy: IMD

Meteorologists called it a matter of deeper diagnosis but there has been a large consensus over the fact that climate change continues to aggravate the situation with increasing global mean temperatures.  

“While it is a matter of research whether such high temperatures this February can be connected to Climate Change, it is very clear that we are living in the era of climate change. There is a definite impact of Global Warming on the increasing trend of temperatures,” said SC Bhan, Scientist, India Meteorological Department.

February remained practically dry on account of no major weather system traveling across the country. Besides this persistence of anticyclone over western parts of India, pushed warm winds over the region. Both the factors combined together paved the way for temperatures to increase, especially over Northwest India.

As on February 27, India was highly rain deficit to the tune of 68%, with the country recording a mere 7.1 mm of rain against the normal of 21.8 mm. Central India was absolutely dry with nil rainfall, followed by Northwest India.

Out of 36 subdivisions in the country, 20 sub-divisions did not receive any rain, 11 were large deficient, 1 deficient, 3 normal, and 1 excess.

Source courtesy: IMD

India to witness increased intensity of heatwave in 2023

According to meteorologists, the increasing trend of the temperatures is likely to continue as well as dominate in the coming summer months as well. As per the forecast released by state-run IMD, enhanced probability of occurrence of Heatwave during March to May season is likely over many regions of Central and adjoining Northwest India.

Source Courtesy: IMD 

March would continue to witness above normal temperatures across most parts of the country. Heatwaves might make an early appearance in some parts of Central India.  However, April and May will have to brave the spells of heatwaves. This anomaly could be attributed to below normal predicted most areas of Northwest India, and west-Central India and some parts of east & northeast India. Normal to above normal rainfall is likely over most parts of peninsular India, east central India and some isolated pockets of northeast India.

Northwest and adjoining parts continue to be in focus as they are prone to heatwave. In a normal scenario, March can be considered to be a lean period for weather activities. Usually by this time, Western Disturbances that are known to drive weather activities across the region, start traveling in the higher latitudes of Himalayas. On the other hand, anticyclone over West India gets more marked, bringing in warm winds from further warmer desert regions. All these factors lead to build up of temperatures.

“Hot weather is here to stay and we should start considering it as a new normal. It has been noticed that rains have declined during March in the last many years. Climate models are indicating similar conditions this year too. It seems that Western Disturbances will continue to evade Northwest India this year too. South India might see some rains on account of few low-pressure areas or depression in South Bay of Bengal, but these systems would not impact other parts of the country,” said Mahesh Palawat, Vice President – Meteorology and Climate Change, Skymet Weather.

March 2022 was the hottest in India since records began 122 years ago. March was extremely dry, with 71 percent below normal over India, making the conditions favourable for local heating from the land surface. The heatwave continued over the month of April and reached its preliminary peak towards the end of the month. By the 29th of April, 70 percent of India was affected by the heatwave.

According to a study on heatwaves by World Weather Attribution, climate change has increased the probability of an event like heatwave in 2022 by a factor of about 30. With future global warming, heatwaves like this will become even more common and hotter. At the global mean temperature scenario of +2C such a heatwave would become an additional factor of 2-20 more likely and 0.5-1.5C hotter compared to 2022.

The 2022 heatwave claimed at least 90 deaths across India and Pakistan, and triggered an extreme Glacial Lake Outburst Flood in northern Pakistan and forest fires in India. The heat reduced India’s wheat crop yields, causing the government to reverse an earlier plan to supplement the global wheat supply that has been impacted by the war in Ukraine. In India, a shortage of coal led to power outages that limited access to cooling, compounding health impacts and forcing millions of people to use coping mechanisms such as limiting activity to the early morning and evening.

Climate Change heatwave in India Western Disturbance in IndiaGlobal Warming

The world witnessed an unprecedented spurt in average global daily temperature above the critical threshold of 2°Celsius over pre-industrial levels (1850-1900 average) on 18th and 19th November. Largely attributed to high concentrations of greenhouse gases in the atmosphere and the ongoing El Nino phenomenon, such temporary breaches in daily temperatures may not be an immediate cause of concern, but sustained over longer periods, can lead to severe and irreversible climate impacts.

Emission of greenhouse gases (GHG) from human activities has made the world 1.1°C warmer since the pre industrial period with the mean global temperature between January and October 2023 being the highest on record. Even at this current level of warming, climate change is already wreaking havoc across the planet—shooting temperatures to extremes, melting glaciers, fuelling wildfires, floods and cyclones. Recent years have witnessed an exponential rise in the frequency and intensity of weather extremes marked by multi-year drought in East Africa, catastrophic flooding in India, China and Europe, extreme heat and relentless wildfires in the United States of America and Canada. India, this year, experienced long durations of extreme heatwave scorching North India, and extreme rainfall events devastating parts of Himachal Pradesh, Uttarakhand and Sikkim.

Vulnerable communities around the world continue to reel under irreparable losses and damages unleashed by such disasters which often undermine their hard-won development gains. The Intergovernmental Panel on Climate Change warns that every additional 0.5°C of warming compared to the present will further exacerbate existing climate risks.

While 196 countries of the world signed the Paris Agreement in 2015 and pledged to limit the increase in the global average temperature to well below 2°C and ideally within 1.5°C above pre-industrial levels, the United Nations Environment Program in their latest Emissions Gap Report 2023 rings the alarm bell that we are moving dangerously closer to permanently overshooting the 2-degree Celsius threshold. The report calls for “immediate, accelerated and relentless mitigation action” to bring down global GHG emissions which set a new record of 57.4 gigatons of CO2 equivalent (GtCO2e) in 2022 with fossil fuel combustion and industrial processes continuing to be its primary sources.

The report cautions that global mean temperatures can cross 3 degrees Celsius above preindustrial levels by the end of the century, unless climate action is significantly accelerated. There is now only 66 percent change of limiting global warming to 2°C (range: 1.8–2.5°C) that also in the most optimistic scenario where all net zero pledges, nationally determined contributions to emission reductions and long-term low-emissions development strategies, are assumed to be fully achieved. Restricting warming within 2°C and 1.5°C using the least-cost pathways would necessitate drastic reduction in global GHGs by 28 per cent and 42 per cent respectively.

However, measures to curb emissions are severely lagging behind, signals the State of Climate Action Report 2023 released by the Systems Change Lab last week. Despite significant strides in scaling up of renewable power sources and the sale of electronic vehicles, global mitigation measures remain “woefully inadequate” to address climate change, finds the report. It further suggests that coal-fired power needs to be phased out seven times faster, “deforestation rates must decline four times faster and increases in the ratio of investment in low-carbon to fossil fuel energy supply need to occur more than ten times faster to limit warming to 1.5 degrees”.

Countries of the world would convene at Dubai this week for the twenty eighth session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP  28) to take stock of the global response to the climate crisis. At a panel discussion on Climate and Energy Geopolitics: The Role of India” organized by Climate Trends, Dr Vaibhav Chaturvedi, Fellow at Council on Energy, Environment and Water (CEEW) suggested that COP 28 is “not just for taking stock, it is a formal process for collective reflection and ratcheting of ambition”. Released ahead of COP28, the Emissions Gap Report therefore, provides an excellent opportunity for states to collectively reflect and systematically amplify their emission reduction targets to align with the long-term temperature goal of the Paris Agreement.  

Global warming Climate Change Emissions Gap Report State of Climate Action Report 2023

The onset month of the Monsoon season, June, ended with deficit rainfall to the tune of 10% of the LPA (Long Period Average). The countrywide cumulative rainfall during June 1-30 was recorded at 148.6 mm against the normal average of 165.3 mm.

Out of the four meteorological sub-divisions, Northwest India was the only region to record excess rainfall. Rest all the regions have recorded deficit rainfall in order of South Peninsula, followed by East and Northeast India and Central India.

Data Source: IMD

The country’s nodal weather agency, India Meteorological Department (IMD) in their earlier forecast had predicted below-normal rainfall is expected over most parts of the country.

Onset, progress, and performance of Monsoon 2023

Monsoon had made a delayed as well as subdued onset over the Indian landmass. Thereafter, the progress of the Monsoon was also not very promising, as there was a delay in the advancement of the Monsoon over the Peninsula and adjoining central India by 7-12 days and Northeast India by 5 days. However, the Monsoon current made an early onset over northwestern parts of the country, covering most of the country by June 28.

Above-normal Monsoon rainfall was recorded over many parts of Northwest and Northeast India, and a few parts of the southern region.

The extremely severe cyclonic storm Biparjoy had a long run in the Arabian Sea from June 6-19. It helped in advance of monsoon during the initial stage, bringing heavy rainfall over Gujarat, Rajasthan, Madhya Pradesh, and adjoining Uttar Pradesh. However, the system took moisture away from the rest of the country, leading to deficit rainfall. Until June 23, the rainfall deficit was 31%.

It was only after Biparjoy weakened, there was the formation of weather systems in the Bay of Bengal that drove the Monsoon subsequently. Two low-pressure systems (LPS) over the north Bay of Bengal on June 9 and June 25 helped in advance of monsoon and good rainfall activity.

Out of 36 sub-divisions in the country, 17 recorded deficit rainfall, 2 large deficit, 7 normal, and 7 excess. Only three subdivisions- Saurashtra & Kutch (196%), West Rajasthan (287%) and East Rajasthan (118%) recorded large excess rainfall. These heavy rains were on account of Cyclone Biparjoy, which had made landfall over the Gujarat coast and moved across Rajasthan.

Meanwhile, MJO (Madian Julian Oscillation), an oceanic phenomenon that favours rainfall over India, was also in a favourable phase, aiding the rainfall.

Extreme Weather Events

Rainfall: 377 stations across the country reported very heavy rain events, the highest in the last five years. Meanwhile, 62 stations recorded extremely heavy rains which was the second highest since 2019. Following are the number of stations that recorded heavy to extremely heavy rains from 2019-2023.

Data Source: IMD

Heatwave: Delayed Monsoon conditions led to heatwave to severe heatwave conditions over several parts of East India and adjoining parts of Central India during the month. Above Normal Heat Wave Days were observed over West Bengal, Odisha, Coastal Andhra Pradesh, Bihar, Jharkhand, Chhattisgarh and adjoining parts of East Madhya Pradesh, Vidarbha & Telangana.

Image Source: IMD

Total Heat wave and Severe heat wave reported in summer of March-June 2023 was 218 Met-Subdivision Days (MSD). It was 3rd highest during the last 23- years after 2019 with 578 MSD and 2022 with 455 MSD.

Monsoon 2023Monsoon in IndiaHeatwave in India Cyclone BiparjoyExtreme Weather in India

India’s vulnerability to extremes of heat in 2019 was 15% higher than in 1990, according to the ‘Lancet Countdown on Health and Climate Change’, a flagship report of The Lancet. It provides periodic updates on the relationship between climate change and public health. It also revealed that India is one of the five countries with the highest exposure of vulnerable populations to heatwaves over the past five years, and the exposure is increasing.

The report tracks 44 indicators of health impacts that are directly linked to climate change. According to the report, there is an unabated rise in the health impacts of climate change and it exacerbates the current health consequences due to the delayed and inconsistent response of countries around the globe.

Heat-related mortality for people older than 65 years increased throughout the study, reaching a record high of almost 0.35 million in 2019, which is 80.6% higher than in the 2000-05 average. India and Brazil reported the highest absolute increase in heat-related mortality between 2018 and 2019, the report said.

The report also found that record temperatures in 2020 resulted in a new high of 3.1 billion more person-days of heatwave exposure among people older than 65 years and 626 million more person-days affecting children younger than 1 year, compared with the annual average for the 1986–2005 baseline. Person-day is equal to one person affected for one day, the total is a product of the number of people and the number of days with heatwave exposure.

The report revealed that 295 billion hours of potential work were lost across the globe in 2020 due to heat exposure with Pakistan, Bangladesh, and India (the three most populous countries in the medium Human Development Index (HDI) Group) reporting the greatest losses (2.5–3 times the world average). 

The economic losses of climate-related extreme events were three times higher in medium HDI countries than they are in very high HDI countries, it noted.

The report found out that the world continues to subsidise fossil fuels despite their effect on climate. Similar results were reported in the Production Gap Report released on Wednesday.  According to the Lancet report in 2018, 65 out of the 84 countries analysed had net-negative carbon prices equivalent to an overall subsidising of fossil fuels.

Many current COVID-19 recovery plans are not compatible with the Paris Agreement and will, therefore, have long-term health implications, the report stated. The economic recovery from the pandemic is already predicted to lead to an unprecedented 5% increase in greenhouse gas emissions in 2021, it said.

Although countries in the very high HDI group have collectively made the most progress in the decarbonisation of the energy system, they are still the main contributors to CO2 emissions through the local production of goods and services, accounting for 45% of the global total, it said. The largest contributors to global consumption-based CO2 and PM2·5 emissions were China, the USA, the EU, and India.

“Governments are spending trillions of dollars on the recovery from the Covid pandemic. This gives us an opportunity to take a safer, healthier, low-carbon path, but we have yet to do so. Less than one dollar in five being spent on the Covid recovery is expected to reduce greenhouse gas emissions and the overall impact is likely to be negative. We are recovering from a health crisis in a way that’s putting our health at risk,” said Maria Romanello, lead author of the report.

Data showed that in 2020, up to 19% of the global land surface was affected by extreme drought in any given month, a value that had not exceeded 13% between 1950 and 1999  threatening water security, sanitation, and food productivity, and increasing the risk of wildfires and exposure to pollutants.

According to the report, globally, 134 of 185 countries had an increase in wildfire exposure in 2017–20 compared with 2001–04. The largest increases in wildfire exposure were observed in the Democratic Republic of the Congo, India, and China, it noted.

Increased flooding, storms and soil and water salinification could put 569.6 million people living less than five metres above current sea levels at risk, it stated. Many of these people could be forced to permanently leave these areas and migrate further inland.

The data also measured the effect of heatwaves on people’s mental health by analysing over six billion tweets over five years from Twitter users around the world. They found a 155% increase in negative expressions during heatwaves in 2020 relative to the 2015-2019 average.

The report warned that as infectious disease transmission increases due to climate change, the healthcare systems are ill-prepared to combat current and future climate-induced health shocks. A 2021 World Health Organization (WHO) survey found out that only 45 of 91 countries in 2021 reported having carried out a climate change and health vulnerability and adaptation assessment. The survey also found 69% of countries reported insufficient financing as a barrier to implementing these plans. 

“Climate change is here and we’re already seeing it damaging human health across the world,” said Prof Anthony Costello, executive director of the Lancet Countdown. “As the COVID-19 crisis continues, every country is facing some aspect of the climate crisis, too. The 2021 report shows that populations of 134 countries have experienced an increase in exposure to wildfires. Millions of farmers and construction workers could have lost income because on some days it’s just too hot for them to work. Drought is more widespread than ever before. The Lancet Countdown’s report has over 40 indicators and far too many of them are flashing red,” he added.

heatwave

It was a sultry September evening, when we sat down with 59-year-old Palayam, a fisherman from Chennai, whose family has depended on the seas for a living for over five generations. Though diminutive in appearance, Palayam’s rough hands and lined face offer a glimpse into his hard life at sea. His grim countenance however lights up when he recalls growing up near the ocean on a steady diet of seafood. Delectable traditional recipes passed on for generations in his community were made with fishes like the Musal Paarai (Paarais are a species of Jackfish), Kondudal Paarai (a Jackfish species), Vanjaram (Seer fish), Kaala meen (Indian Salmon), Mosidi (Orange snapper) and Kurali (Emperor fish). 

“We were eating seafood at least 5-6 times a week. Only after the family was fed, was the remaining catch taken to the market to sell. We were content and earned enough,” he explains. “But today, the catch I bring back is only enough to sell in the market and make enough money to run my family. On some days, I even come back with nothing worth selling,” he admits defeatedly.

This fisherman can barely remember the last time he ate seafood, even three days in a row.

“We have been eating vegetables and eggs for the past five days. My children have grown up without seafood as a prominent part of their diet. I can’t constantly afford other proteins like chicken or mutton,“ he says. “Species like the Malabar King fish, seer fish, Silver pomfret and King Crabs, which my grandfather so casually brought home, are now not that easily available in the sea. And even if I want to buy them, the rates are just unaffordable,” he adds.

This fisherman’s lament not only echoes through his community but also moves along the upper echelons of the supply chain in the fishing industry in Chennai, as species that were once easily available are now proving to be near impossible to catch in large quantities. While overfishing and pollution are major stressors for the marine environment, scientists are now finding that climate change and the resultant warming of seas and other water bodies are proving to be the fatal blow that has completely changed the ecosystem. A growing body of scientific evidence, backed by anecdotes from the fishing community and hoteliers, point to a bleak future for the seafood industry if the climate emergency remains unaddressed.

CONNECTING SCIENCE TO EXPERIENCE

Research spanning the last two decades has repeatedly shown that increasing sea-surface temperatures are affecting the fish population by harming both their fundamental source of sustenance and their habitats. For instance, there has been a consistent effort to establish the link between marine heatwaves, reducing phytoplankton and increasing coral mortality.

Marine heatwaves (MHW) are periods of extremely high temperatures in the ocean (above the 90th percentile which means temperatures are in the top 10% from the data). These events cause habitat destruction due to coral bleaching, seagrass destruction, and loss of kelp forests, affecting the fisheries sector adversely.

Image: Example of a marine heatwave in the Bay of Bengal during April–May 2020. Image Source: Advancing Earth and Space Science

These heatwaves used to be rare in the tropical Indian Ocean, but now they have become an annual affair. Studies have reported high Sea Surface Temperature (SST) conditions in the western Indian Ocean, Arabian Sea, and the Bay of Bengal region (Andaman Sea) and also point out big impacts on the marine ecology due to intense warming in these regions, suggesting that marine heatwaves are behind these events.

According to a research paper by Advancing Earth and Space Science, western Indian Ocean reported 66 marine heatwave events during the 1982–2018 period, in which 21 events occurred during June–September months (Indian Monsoon season) of every given year. Meanwhile, the north Bay of Bengal region witnessed 94 marine heatwave events, and 34 out of these occurred during June–September.

There was a significant rise in annual Marine Heatwave frequency during 1982–2018 at a rate of 0.14 events per year for the western Indian Ocean and 0.09 events per year for the north Bay of Bengal. The western Indian Ocean region experienced the largest increase in marine heatwaves in the region at a rate of about 1.5 events per decade, followed by the north Bay of Bengal at a rate of 0.5 events per decade. 

IMPACT OF WARMING ON FOOD CHAIN IN OCEANS

Phytoplankton essentially forms the basis for aquatic food webs. It is one of the main sources of sustenance for primary consumers such as zooplankton, small fish, and crustaceans. These primary consumers are in turn fodder for bigger fish, small sharks, whales and the like.

“There is an overall decline in marine phytoplankton mass in the Indian seas, as observed from the chlorophyll data. This is more in the Arabian Sea as compared to the Bay of Bengal. The decline in phytoplankton in the Bay of Bengal is observed in some of the coastal seas and the northernmost part of the basin. We find that this can cascade through the food chain and affect the fisheries too,” says Dr Roxy Mathew Koll, a climate scientist from the Indian Institute of Tropical Meteorology.

Laboratory experiments conducted on seven species of phytoplankton found that while the rate of multiplication was faster at higher temperature, the decay too set in earlier.

Corals meanwhile are made up of thousands of tiny animals called polyps. They provide habitat for a large variety of marine life, including various sponges, oysters, clams, crabs, sea stars, sea urchins, and many species of fish. According to scientists, corals occupy less than 0.1% of the ocean’s surface area but support close to 25% of marine biodiversity.

A paper titled ‘Exceeding 1.5°C global warming could trigger multiple climate tipping points’ explains that the entire marine food web is in danger when corals collapse. Ocean acidification, which essentially signifies increased pH balance of the water due to absorption of excess carbon dioxide has been mentioned as a factor that is worsening the existing crisis. 

‘When water temperatures exceed a certain threshold, coral irreversibly expel their symbiotic algae resulting in coral bleaching, thereby triggering coral death. Ocean acidification worsens warming-induced degradation. Coral collapse would remove one of the Earth’s most bio-diverse ecosystems, affecting the wider marine food web, ocean nutrient and carbon cycling, along with livelihoods of millions of people worldwide.

Experts say that marine life in the Bay of Bengal, which is experiencing more heatwaves than ever, is facing extreme stress as outlined in this study.

“Our most recent research shows that the Bay of Bengal is susceptible to marine heatwaves, and that the intensity and frequency of these heatwaves are increasing. Marine heatwaves have been found to be destructive for the marine ecosystem, leading to mass mortality of corals, marine invertebrates and fishery collapse,” confirms Dr Roxy Koll.

On the ground in Chennai, powerful first hand accounts from fishermen, seafood suppliers and procurement personnel give voice to the changes happening within our seas and oceans. 

WHAT IS HAPPENING TO FISH?

“Even 10 years ago, if I took my boat and went up till Kotturpuram I would be able to get at least 10 kilos of Kaala Fish (Indian Salmon) where the river meets the sea, but now getting even 2 kilos is considered a jackpot,” says Palayam.

This is a consistent pattern noticed across Chennai. From suppliers and procurers to the chefs of top restaurants, the shift in what is being caught at sea has left the industry in a fix.

“Until 15 years ago, we would get fish like Sudumba (False Trevally) and Sura (shark) very easily from the sea. Even in prawns, we were getting six varieties from the sea and now that has reduced to three. The same goes for fish like Mahi Mahi, mussels and lobsters,” says Vijay Kumar, the owner of Blue, a seafood contractor that supplies to 40 hotels and restaurants in Chennai and neighbouring Mahabalipuram. 

“I don’t know what has happened. Have we eaten too much? Is it pollution or is it climate change? The fish have gone very deep into the sea and they seem to be moving to colder waters. Fish that we would get near the surface before are now getting caught in nets meant for deep sea fish,” he adds.

The supplier is right on all three counts, say researchers and marine scientists who have been studying the effects of global warming on seafood catch.

“The way we see it, unsustainable fishing and habitat degradation are like comorbidities for the fish, and climate change is like COVID-19. Any one of these issues by itself may not be life threatening, but together they impact the population of species heavily,” says Dr E Vivekanandan, former principal scientist at Central Marine Fisheries and Research Institute (CMFRI). “As far as climate change and fish population are concerned, there are three major issues. One is the warming sea water, the second is the acidification of oceans and the third is reduction in oxygen concentration in some locations in the sea. All of these problems cause fish, which are very mobile organisms, to keep moving to more favourable conditions.” 

WHAT HAPPENS IN WARMING WATERS?

According to a study by the Central Marine Fisheries and Research Institute (CMFRI), certain fish have been found to change their behaviour and descend to deeper waters in the last two decades, as temperatures have risen.

The study that focussed on mackerel, a fish that normally occupies surface and subsurface waters, stated, ‘During 1985-89, only 2% of mackerel catch was from bottom trawlers, and the rest of the catch was contributed by pelagic gear such as drift gillnet. During 2003-2007, it is estimated that 15% of mackerel catch was contributed by bottom trawlers along the Indian coast.’

In another report, Ivan Nagelkerken of the University of Adelaide was quoted explaining this phenomenon.

“Species are extending their ranges pole-wards as the oceans warm due to climate change. This process, known as tropicalisation of temperate ecosystems, means tropical species are mixing with temperate species and creating novel ecological interactions.”

According to Nagelkerken, mixed shoals of tropical and temperate species became less cohesive under future climate conditions and showed slower escape responses from potential threats. Strong shoal cohesion and coordinated movement, whether to acquire food or evade predators, are important for fish survival.

This movement of species from traditionally mapped areas is being observed by the fishing community across the world, from Canada to even Ghana.

A study titled ‘Disentangling tropicalization and deborealization in marine ecosystems under climate change’ claims that species are moving towards the poles in search of cooler waters. Species that are usually found in subtropical and tropical underwater environments for instance are now being found in temperate environments. This is a cause of concern as it clearly proves the movement of fish from tropical waters that were considered the right temperature for their habitation to temperate waters that are cooler by virtue of being closer to the poles.

According to a report by the Intergovernmental Panel on Climate Change (IPCC), ocean acidification and global warming are interfering with the way fish interact in groups, posing a threat to their survival which could affect seafood supplies.

Marine ecosystems worldwide have shown an increased dominance of warm water species following seawater temperature rise, with parallel changes in the species composition of fish catches since the 1970s, according to the IPCC report.

OCEAN ACIDIFICATION

Ocean acidification too is a byproduct of global warming. It occurs because human activities increase the levels of carbon dioxide in the atmosphere and in turn more of the greenhouse gas is dissolving into the ocean. The ocean’s average pH level is supposed to be around 8.1, which is basic (or alkaline). However, as more CO2 is released into the atmosphere, the ocean continues to absorb more of the greenhouse gas, resulting in a pH decrease and the ocean becoming more acidic.

Dr Vivekanandan points out that acidification is dangerous because it affects the fish’s physiology.

“Marine organisms have a certain calcium content based on the species. When acidity of the ocean increases, it reduces calcification. When fishes are juvenile they have to form a vertebral column and due to the chemical reaction caused by the increased addition of carbon dioxide to sea water, more bicarbonates are forming and affecting the calcium content in fish. This affects both juvenile and larger fish and the vertebrae of these organisms display deformities,” he explains.

In addition to this, scientists also observe that the size of various fish is changing due to temperature rise and acidification. These findings are further supported by anecdotes from seafood procurement personnel and chefs from Chennai.

DOES SIZE MATTER?

Chef N Kannan, a veteran in the hotel industry, who has worked with star hotels in Tamil Nadu for 25 years, witnessed first hand the shrinking of the prawns he was serving his customers.

“We need 400-500 gm of fish to present to our chefs,” says D Shankar, who handles procurement of seafood for The Park in Chennai. “But we don’t get the grammages. When asked, vendors just put their hands up in the air and blame climate change. This leaves us with no choice but to limit our menus to provide the best quality and quantity,” he adds.

Squids, for instance, he says, are required to be a minimum width of two inches to be served in a 5 star hotel. But these are no longer available.

“We used to order mackerels as they would give a lot of meat. But now we no longer get the larger-sized mackerel, so we have moved to using the red snapper,” he says.

Chef Kannan, too, points out that the mackerels and Kaala fish (Indian Salmon), if they ever got it, were becoming smaller in size.

Chef Ashutosh Nerlekar, who runs the kitchen at The Park in Chennai confirms this observation.

“In a hotel like ours, seafood like lobsters have to be a certain size to be fit to be served,” says Chef Ashutosh. “We currently grill our lobsters and if the size is too small, it shrivels up and we can’t present it. The shell looks larger,” he adds.

Fishermen and one section of scientists believe that the reduction in the size of individual fish is because of overfishing, which does not allow marine life to grow to their full extent. While this could be one reason, studies show that warming waters due to climate change is also responsible for the change in the physical attributes of the catch.

Evidence from theoretical modeling and empirical data has shown that one of the main expected responses of marine fishes to ocean warming is decrease in body size. One reason for this is that the oxygen supply required by large fish cannot be met in such habitat. Another reason offered is that the metabolism of fish increases in warmer waters.

“When the temperature increases, the metabolism of fish is faster and their oxygen consumption increases. Lot of energy is spent on respiration. Growth of the fish reduces and is faster,” says Dr Vivekanandan. “It achieves one year’s growth in just 7-8 months. So the fish remains smaller and doesn’t reach a larger size. Its longevity also reduces. Because of the higher temperature, everything is happening at a very fast pace,” he explains.

If this trend continues, scientists predict that many commonly-eaten fish could face extinction due to climate change. 

Another study titled ‘Climate change ‘double whammy’ could kill off fish species’, has stated that  climate change will not only force fish to evolve to a smaller size, but it can also reduce their ability to move to more suitable environments. 

Professor Chris Venditti, an evolutionary biologist at the University of Reading, and co-author of the study has said that fish will get left behind in evolutionary terms as sea temperatures rise faster than ever. And this in turn could have serious implications on food security as species we depend on for sustenance become increasingly scarce in years to come. 

So how do we battle this fast-approaching problem? We will bring you the information in the next story of this series.