Written by Raghu Murtugudde The past year, 2023, was the warmest since records began in 1850, Europe’s Copernicus Climate Change Service (C3S) said recently. Copernicus, a programme of the European Union built as Europe’s Eye on Earth, just released a summary of all the weather records broken in 2023, along with the smorgasbord of disasters strewn across the planet. One noteworthy statistic is that each day of 2023 was more than 1℃ above the average of the same day over the 1850-1900 baseline. What happens next? The short answer to this question, unfortunately, is that it will be more of the same, but we don’t know when and we cannot pinpoint where. The vague but supposedly ‘useful’ information being put out in large quantities by the climate community is actually not usable or actionable even at national levels, let alone subnational levels. The action that is argued vehemently to be very urgent is all but impossible without location-specific forecasts for multiple seasons and years. Investments in broad climate adaptation and mitigation actions, such as afforestation and climate-resilient infrastructure, may not be effective and can also be expensive if done everywhere. Were we expecting the monstrous warming of 2023? A decadal forecast was made before 2023 that the earth would cross the 1.5℃ warming threshold sometime between 2022 and 2026. Again, a warning with no specific action possible at local levels, other than to continue the ongoing mitigation efforts. A forecast for 2024 says the warming will continue. Even if 2024 does turn out to be warmer than 2023, it is unlikely that the droughts, floods, cyclones, hurricanes, wildfires, heatwaves and such will occur at the same locations or with the same intensity. Which again means we can hardly do anything better than to hope for the best and prepare for the worst with limited resources. The penalty of expending resources on disaster preparedness, management and recovery means that investing in building climate resilience for the longer term becomes progressively harder. Why was 2023 so warm and what will El Niño do now? It is now clear that the record warming in 2023 was not just a combination of El Niño and global warming. Other factors such as reduced sulphate aerosols (which scatter sunlight and cool the atmosphere), the water vapour thrown up by the undersea volcanic eruption of 2022 (the Hunga-Tonga-Hunga-Ha’apai volcano in the southern Pacific Ocean), and emissions from extensive wildfires likely amplified the warming. All forecasts show that this El Niño will likely dissipate by spring and we are likely to head into a La Niña by this summer. Two things are to be noted here. Even though the El Niño was forecast at the very beginning of 2023, claims of it being of historic strength have not materialised. The 2015-16 El Niño was much stronger. Also not forecast was the different pattern of the warming in the tropical Pacific during the 2023 El Niño. Unlike normal El Niños, this El Niño had warmer-than-expected sea surface temperatures in the western tropical Pacific. While such a pattern was noted before as the superposition of global warming and El Niño, the consequences of this altered pattern remain to be fully understood. What if a La Niña does emerge in 2024? If the current forecasts hold true and a La Niña does emerge this summer, the ocean will begin to soak up heat like a sponge. The vast expanse of cold waters called the Cold Tongue, stretching from the South American coast to the International Date Line, take away the heat from the atmosphere and hide it in the ocean till the next El Niño. A three-year La Niña from 2020 to 2022 may have been one reason why the 2023 El Niño grew to be so strong. Another thing to keep in mind is that global warming tends to produce cold waters in the Cold Tongue and thus dampens global warming. Is it possible that we will have an accelerated cycle of multi-year La Niñas and more frequent El Niños? It would be important to know this but the models have great difficulty in capturing global warming-related cooling in the Cold Tongue region. What about 2024 and beyond? This brings us back to the crucial question of how to respond to the alarming warming of 2023. It is hardly sufficient to know that 2024 may be warmer and that we will continue to have more years like 2023. Crisis management is better served by early warnings at days to weeks for food, water, energy, health, transportation and such. The fog-driven flight cancellations are a good example of the socioeconomic devastations that can be alleviated with skillful early warnings. The remarkable cooling during 2023 over a large part of India amid the accelerated global warming is a stark reminder of the need for location-specific decadal outlooks, to plan for such events as erratic monsoons, killer heatwaves and disruptive fog episodes. Raghu Murtugudde is a professor of climate studies at IIT Mumbai. He is also an Emeritus Professor at the University of Maryland
