Managing climate risk
THE year 2021 saw many countries experiencing exceptional weather extremes. Temperatures reached 500C in Western Canada and the US; record high temperatures were seen in many parts of the Mediterranean; a monthÕs worth of rain falling over just a few days led to floods in Europe and China; India experienced long dry spells and heavy rain during the summer and now the winter monsoon; for the first time rain instead of snow fell on the Greenland ice sheet; there was a second year of drought in South America; forest fires raged in many parts of the world including in Siberia because of exceptionally high temperatures.
Many of these extreme weather events have been attributed by scientists to long-term changes in the average temperature of the earth, a trend that we call climate change. Scientists have warned the world about this trend for several decades and their forecasts have become increasingly alarming. That and the widespread experience of weather extremes has led to a greater sense of urgency in addressing climate change related risks. What follows spells out these risks and what needs to be done globally to mitigate them.
The earth is habitable because of the presence of carbon dioxide, methane and other greenhouse gases (GHGs) in the atmosphere. In the absence of these GHGs the average temperature of the earth, at which incoming and outgoing radiation are in balance, would be around -190C, a level at which human and most other life forms cannot be sustained. The GHGs in the atmosphere reflect back to earth some of the outgoing radiation and raise this average temperature to a higher level, which at present is around 150C. This average temperature has fluctuated up and down through the earthÕs history of ice ages and thaw periods. However, these changes took place slowly over centuries or even millennia.
Our concern today is that we are facing the threat of substantial temperature rise over a much shorter period measured in years and decades. The accumulation of greenhouse gases that we see now is huge by historical standards. In 2019, atmospheric CO2 concentrations were higher than at any time in at least two million years, and concentrations of CH4 and N2O were higher than at any time in at least 800,000 years. The bulk of the increase has taken place after the industrial revolution that increased the use of carbon dioxide emitting fossil fuels and much higher economic and population growth, particularly after 1950.
Because of the accumulation of GHGs an increase of about 10C has already taken place relative to the average temperature in the last half of the 19th century. Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years. Moreover, it is now clear that most of this temperature increase is because of human activities, most particularly the use of carbon-based fossil fuels like coal, petroleum and gas. This much faster rate of temperature change leaves little time for ecosystems and human beings to adjust to a higher temperature environment and poses major threats of disruption and distress. That is the climate risk that the world community is now trying to address.
The concern about climate change linked to anthropogenically induced temperature rise led in the late eighties to governments agreeing within the UN framework to establish a scientific body for building a consensus on the facts and projections about climate change, the Inter-governmental Panel on Climate Change (IPCC).
The most recent report of the IPCC,1 that is part of its sixth assessment which will be completed only in 2022, has pointed out that each of the last four decades has been successively warmer than any decade that preceded it since 1850. Global surface temperature in the first two decades of the 21st century (2001-2020) was 0.99¡C higher than 1850-1900. When it comes to consequences of the temperature rise, the Report states that
* Globally averaged precipitation over land has increased since 1950, with a faster rate of increase since the 1980s.
* Mid-latitude storm tracks have likely shifted poleward in both hemispheres since the 1980s, with marked seasonality in trends.
* Human influence is very likely the main driver of the global retreat of glaciers since the 1990s and the decrease in Arctic Sea ice area between 1979-1988 and 2010-2019.
* Human influence very likely contributed to the decrease in Northern Hemisphere spring snow cover since 1950.
* The global upper ocean (0-700 m) has warmed since the 1970s and human influence is the main driver and human-caused CO2 emissions are the main driver of current global acidification of the surface open ocean.
* Global mean sea level increased by 0.20 m between 1901 and 2018.
The IPCC report also focuses on extreme weather events. It has assessed that the 10C temperature rise that we have experienced so far has increased the incidence of hot temperature extremes that came once in ten years in the last half of the 19th century to 2.8 times now. If the average global temperature were to increase by 1.5-20C this would go unto 4.1-5.6 times a decade. A similar comparison for heavy precipitation shows an increase of 1.3 times now and 1.5-1.7 times with a 1.5-20C temperature rise and of droughts to 1.7 times now and 2-2.4 times with a 1.5-20C temperature rise. Apart from this we will face a rising incidence of cyclones and storms and sea water intrusion in coastal areas because of the rise in sea level because of the temperature rise.
The global forecasts are helpful. But for effective management we also need regional assessments as the impact of the temperature rise will vary from place to place. A recent assessment of climate risks that India faces was prepared by the Department of Earth Sciences2 and a summary of that is as follows:
* The annual mean near-surface air temperature over India has warmed by around 0.7¡C during 1901-2018 with the post-1950 trends attributable largely to anthropogenic activities. Atmospheric moisture content over the Indian region has also risen during this period.
* Sea surface temperature (SST) in the tropical Indian Ocean has risen by 1¡C on average over 1951-2015 and is projected to increase further during the 21st century.
* Despite the rise in temperature, there has been a declining trend in summer monsoon precipitation since 1950 with particularly notable decreases in parts of the Indo-Gangetic plains and the Western Ghats attributable to the cooling effects of aerosols and land use changes, which have more than offset the precipitation enhancing tendency of GHG warming in the past 6-7 decades.
* The frequency of localized heavy precipitation occurrences has risen significantly over Central India in the past 6-7 decades.
* Warming due to increasing concentration of atmospheric GHGs and moisture content is generally expected to strengthen the Indian monsoon and climate models project a considerable rise in the mean, extremes and interannual variability of monsoon precipitation by the end of the century.
* India has witnessed a higher frequency of droughts and expansion of drought-affected areas since 1950.
* Flooding events over India have also increased since 1950, in part due to enhanced occurrence of localized, short-duration intense rainfall events and flooding occurrences due to intense rainfall are projected to increase in the future.
* Higher rates of glacier and snowmelt in a warming world would enhance stream flow and compound flood risk over the Himalayan river basins. The Indus, Ganga and Brahmaputra basins are considered particularly at risk of enhanced flooding in the future in the absence of additional adaptation and risk mitigation measures.
* The North Indian Ocean (NIO), the ocean near India rose at a rate of 3.3 mm per year during 1993-2017 similar to the global mean sea level rise.
* The frequency of very severe cyclonic storms over the NIO during the post-monsoon season has significantly increased in the past two decades and with continued global warming, the frequency is projected to further increase during the 21st century.
* The Hindukush Himalayas (HKH) underwent rapid warming at a rate of about 0.2oC per decade during the last 6-7 decades and experienced a significant decline in snowfall and glacial area in the last 4-5 decades.
Quite simply, the way things are going our children and grandchildren will live in a world with many more hot spells with temperatures going up to 500C, much more rain on fewer days, frequent floods, intrusion of sea waters in coastal areas and more cyclones and storms.
The atmosphere of the earth is shared by all living things on earth and the accumulation of greenhouse gases does not respect any political boundary. But the actions which have to be taken to address the consequences of this accumulation are the responsibility of each country. Hence addressing the risks arising from rising emissions of GHGs must take the form of global cooperation with commitments written into treaty obligations.
The growing concern about climate risks led to a negotiating process aimed at deciding what each nation should do and led to a global treaty, the UN Framework Convention on Climate Change (UNFCCC) that was opened for signature in 1992. It entered into force in 1994 and the first Conference of Parties (COP) was held in 1995 under the chairmanship of the then Environment Minister of Germany, Angela Merkel.
Since the states had to act on impacts that would take place only decades into the future, a process for building a consensus on the underlying science and the facts and projections was necessary. The five assessments that the IPCC has so far presented have strengthened the scientific consensus on the facts and the projections, and skepticism about the anthropogenic impact on climate is now limited to those who have a commercial interest in fossil fuels. Even among those with a vested interest there has been a rapid move away from questioning the reality of climate change.
Initially the focus in the negotiations was on the commitments of developed countries who were largely responsible for the accumulation of the principal greenhouse crash, carbon dioxide, in the decades since the start of the industrial revolution. In the mid-Õ90s the Kyoto protocol was negotiated where the developed countries, other than the largest emitter, USA, accepted modest commitments to reduce their emissions. By the start of the millennium the pressure for action shifted with the large increase in emissions from a fast-growing China. The diplomatic process then shifted to diluting the distinction between developed and developing countries and making commitments voluntary national pledges rather than globally negotiated commitments. This led to the Paris Agreement of 2015 limiting likely temperature increase to 20C, with an aspirational goal of 1.50C included. All countries were required to and filed nationally determined contributions (NDCs) to the global effort.
In 2018 the IPCC produced a report3 comparing the likely impact of a 1.5¼C increase versus a 2¼C increase. The report said that limiting global warming to 1.5¼C would lead to lower mean temperature in most land and ocean regions, fewer hot extremes in most inhabited regions, fewer heavy precipitation incidents and lower the probability of drought and precipitation deficits in some regions. A rate of sea level rise would be slower and enable greater opportunities for adaptation in the human and ecological systems of small islands, low-lying coastal areas and deltas. Limiting global warming to 1.5¡C compared to 2¡C would lower the impacts on terrestrial, freshwater, and coastal ecosystems. This report and the growing instances of extreme weather events generated a sense of urgency prior to the November 2021 Glasgow meeting of the Conference of Parties (COP) to the UN Framework Convention on Climate Change (UNFCCC).
meeting has had limited impact on future projections
of temperature rise and its consequences. The outcome of Glasgow on commitments for emission reduction relative to what was pledged after Paris in 2015 is quite limited and amounts to about 3.3-4.7 billion tonnes of CO2 equivalent as against the reduction of 20-25 billion tonnes that is required if we wish to contain temperature increase to the agreed Paris goal of 20C or the aspirational goal of 1.50C. There were some sectoral pledges by groups of countries at Glasgow on methane emission reduction, exiting from coal-based power mostly beyond 2030, accelerating the move to zero emission road vehicles and halting and reversing forest loss and land degradation by 2030.
A spate of announcements of target dates by
which a country would reduce its emissions of greenhouse gases to net-zero were
made before and during the Glasgow meeting. The qualification ÔnetÕ before
ÔzeroÕ implies that part of the transition to zero could be measures like
reforestation or carbon capture from emissions before it reaches the atmosphere
and then storing or converting it to some useful product. However, the time
path from now to the announced net-zero dates would still
lead to emissions that far exceed the limit for keeping the 50:50 chance of temperature rises below 1.5¼C.
Focusing on six major emitters, each of whom accounts for emissions over a billion tonnes a year at present, USA, China and Russia would have to reduce their emissions to a quarter, Japan to a third and the EU and UK to about half of the current projection after taking account of the promises made. The target dates would also have to be brought forward to well before 2050. India, which is one of the six major emitters, would have to reduce its projected emissions to about four-fifth of what it has promised. That goal, unlike the case for the other five major emitters is quite achievable and so are the goals that it has promised for 2030.4
Based on current trends and after taking all promises into account we are not on target to stay below 1.5¼C or even 2¼C. The negotiating process has now stretched over a quarter-century but has led only to limited progress in reducing climate risks. This can be seen in the increase in cumulative emissions from domestic production between 1990 and 2020 by 15 countries which are major emitters and account for over 80% of global emissions.
Except for the EU and Russia (where the fall is more due to the collapse of the old communist economy) none of the major emitters has restrained emission growth. These numbers bring out the very high growth of emissions in China and, to a lesser degree, in India. The last column compares the emissions that arise from consumption in a country to those that arise from production activities. This shows that the culpability of the developed world would look even worse if we were to correct for their transfer of emission intensive demands to other countries, which explains the lower consumption-based emissions in China, India and the fossil fuel exporters.
The root of the problem lies in the fact that the negotiating process is taking place in the classical diplomatic environment of sovereign countries bargaining for concessions from each other. Climate risks are shared global risks and we need a process that considers responsibility, both as culpability for past emissions which have caused the problem and as duty to use oneÕs capacity not just for oneself but also to help others who are vulnerable and less endowed with financial and technological capacity. This is what one would expect and get if a village were to be warned that it is likely to face a flood. But the global village lacks the ethos of joint responsibility.
There is a window of opportunity in the decisions taken at Glasgow asking countries to raise their commitments to a level that will bring us closer to the 1.50C path. But that will not happen unless the countries agree on principles of climate justice spelt out in terms of emission limits. Since even with a 1.5¼C increase there will be significant stress and higher weather risks, the global agreement must also include commitments by the rich nations who are more culpable and better placed financially and technologically to provide the required assistance to poorer, more vulnerable countries for mitigation and adaptation.
India is well placed to pursue this line of diplomacy as, amongst the major emitters, the gap between what it has promised to do and what it should under any reasonable principle of res-ponsibility is relatively small. It is also a country that is rated as the seventh most vulnerable and hence needs to push hard for substantial acceleration in mitigation activities. We have the capacity and the responsibility and must take this lead to save the lives of our children and grandchildren.
1. Climate Change 2021, The Physical Science Basis: Summary for Policymakers. IPCC, August 2021.
2. Assessment of Climate Change over the Indian Region. Ministry of Earth Sciences, GOI, New Delhi, 2020.
3. Global Warming of 1.5¼C, IPCC, October 2018.
4. AuthorÕs calculations based on the promises made, the limits set by the IPCC for a 50:50 chance of staying below 1.5¼C and the principle that the utilization of this limit should be equal in per capita terms over the period 2020-2050.