The Intergovernmental Panel on Climate Change (IPCC), the scientific group put together by the United Nations to assess all global science related to climate change, published the third instalment of its Sixth Assessment Report (AR6), prepared by Working Group (WG) III, in April 2022. The first instalment prepared by WG I was released in August 2021. Titled ‘The Physical Science Basis’, it focused on the physical science of climate change and on how human activity has changed the climate in unprecedented ways. The second report by WG-II was released in February 2022, entitled ‘Impacts, Adaptation and Vulnerability’. It showed that we are now stuck with some of the worst effects of climate change, whether we decarbonise or not. The third and final instalment called ‘Mitigation and Climate Change’, focuses on the measures that are necessary to halt global warming. (By mitigation, the IPCC means an anthropogenic intervention to reduce the sources or enhance the sinks of greenhouse gases; and by adaptation it means adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities.) The ARC 6 third report builds on the findings of the earlier reports to set out what can be done to limit temperature rise by the end of the century. Though the third instalment is the final AR6 report, the IPCC intends to bring out a synthesis report combining the reports of the three working groups towards the end of 2022.
As the name suggests, AR6 is the sixth round of reports released by the IPCC. The earlier reports were in 1990, 1995, 2001, 2007 and 2013. A Special Report on Impacts of Global Warming of 1.5 °C was released by the IPCC in 2018.
Main Points of the Report
The highlights of the report are as follows:
Alarming Rise in GHGs
- Greenhouse gas (GHG) emissions, which cause global warming, continue to rise, and the plans to address climate change, as they exist at present, are not adequate to limit warming to 1.5 °C above pre-industrial levels. (According to scientists, this is a safe threshold—the ‘1.5 °C target’ or ‘1.5 °C scenario’. If 2 °C is taken as the limit for global warming, humankind may still manage, though things can get bad, but anything beyond 2 °C can be catastrophic. The rise in GHG emissions between 1850 and 2019 in the world is equivalent to 2,400 billion tonnes of carbon dioxide, 42 per cent of which took place in just the last 30 years and 17 per cent in the last ten. The 1.5 °C target requires the world to limit emissions to 500 billion tonnes more (called carbon budget).
- In 2019, global net anthropogenic GHG emissions stood at 59 gigatonnes of carbon dioxide equivalent (GtCO2e), 54 per cent higher than in 1990. (Net emissions stand for emissions after deduction of emissions that the world’s forests and oceans absorb.)
Anthropogenic Impact Prominent
- The growth in anthropogenic emissions, i.e., emissions originating from human activities like the burning of coal for energy or cutting of forests, has been driven mainly by emissions of carbon dioxide from the burning of fossil fuels and the industrial sector, as well as emissions of methane. The proportion of emissions taken up by land and ocean (in carbon sinks) decreases with increasing cumulative CO2 emissions. This is projected to result in a higher proportion of emitted CO2 remaining in the atmosphere.
- Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. This is to be seen in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened since AR5.
Climate Change Proportional to Global Warming
- Changes in the climate system become larger in direct relation to increasing global warming. They include increases in the frequency and intensity of hot extremes, marine heatwaves, heavy precipitation, and, in some regions, agricultural and ecological droughts; an increase in the proportion of intense tropical cyclones; and reductions in Arctic sea ice, snow cover and permafrost. Monsoon precipitation is projected to increase in the mid- to long-term at the global scale, particularly over South Asia and South East Asia, East Asia and West Africa apart from the far west Sahel.
Some Improvements
- There are some improvements. The average annual rate of growth slowed to 1.3 per cent per year in the period 2010–19, compared to 2.1 per cent per year in the period 2000–09. At least 18 countries have reduced GHG emissions for longer than 10 years on a continuous basis due to decarbonisation of their energy system, energy efficiency measures, and reduced energy demand, and 24 countries have sustained their GHG emissions reductions for over a decade.
Emissions Unevenly Distributed
- The emissions are not evenly distributed. Carbon inequality continues with the wealthiest countries accounting for a disproportionately high amount of emissions compared to the developing countries, even though it is the developing countries that are at the receiving end of severe impacts of climate change. The least developed countries (LDCs) emitted only 3.3 per cent of global emissions in 2019; in the period 1990–2019, their average per capita emissions amounted to only 1.7 tonnes CO2e, while the global average was 6.9 tonnes CO2e. In the period 1850–2019, the LDCs contributed less than 0.4 per cent of the total historical CO2 emissions from fossil fuels and industry. Some 41 per cent of the world’s population inhabited countries with emissions under 3 tonnes CO2e per capita in 2019, while 35 per cent of people live in countries whose per capita emissions are much beyond the equivalent of 9 tonnes of CO2e. Obviously, the impact of those who emit more is felt most by the poor. (The per capita emissions for India are 1.8 tonnes.)
Climate Change Pathways
- The nationally determined contributions (NDCs) or the current pledges made by the signatories of the Paris Agreement, on being added up, would exceed 1.5 °C in this century, thereby failing the Paris Agreement’s mandate. The main contributor to this failure is the CO2 emissions from the existing and planned fossil fuel infrastructure.
- Mitigation is called for as it be ‘impossible’ to stay below1.5 °C with ‘no or limited overshoot’ (overshoot being the period of time in which warming is increasing past the 1.5 °C mark and then cooling back down) without stronger climate action this decade.
- In order to limit global warming to around 1.5° Celsius above preindustrial levels, GHG emissions need to reach their highest peak before 2025, according to scenarios analysed by the IPCC. By 2030, GHG emissions must be reduced by 43 per cent.
- The scenarios of a broad range of future greenhouse gas emissions and global climate outcomes could be classified into eight different ‘climate categories’ based on 21st century warming outcomes. These categories are C1 through to C8. They have been devised on the basis of climate model emulators, called MAGICC (Model for the Assessment of Greenhouse Gas Induced Climate Change) and FaIR (Finite amplitude Impulse Respouse). Seven illustrative pathways (IPs) were defined representing the results under current policies (Cur-Pol), results in case 2030 commitments are met but limited additional climate policies are enacted (Mod-Act), and five deep mitigation strategies that limit warming to below 2 °C or to 1.5 °C with different types of approach being put to use.
- Three of the IPs which would lead to climate outcomes that limit warming to 1.5 °C with ‘no or limited overshoot’ (C1) are shifting development pathways, low demand, and high renewables; C2 would involve extensive use of net-negative emissions; and C3 would be characterised by a gradual strengthening of current policies, and would have the likelihood of limiting warming to below 2 °C by 2100. The Mod-Act pathway—in which countries meet their 2030 commitments, but with little additional climate action—likely results in warming of between 2.5 °C and 3 °C by 2100 (C6).
- Net-zero CO2 emissions would be reached by C1 pathways between 2050–2055 on average, with a range of between 2035 and 2070 across all the scenarios assessed; by C2 between 2055 and 2060 with a range from 2045 to 2070; and by C3 scenarios between 2070–2075 with a range of 2055 to 2100 or later. Both C1 and C3 pathways reduce methane emissions by around 50 per cent by 2050, with similar reductions of nitrous oxide (N2O).
- The C1 pathway appears rather difficult to achieve since the IPCC special report of 2018, due to four years of flat or modestly increasing global emissions. In both C1 and C2 cases, other GHG emissions will have to be reduced significantly, but are difficult to fully get down to zero as the sources of methane and nitrous oxide emissions are diverse.
Mitigation Strategies
- A mix of strategies can help avoid locking in CO2 emissions. These include retiring existing fossil fuel infrastructure, cancelling new projects, retrofitting fossil-fuelled power plants with carbon capture and storage (CCS) technologies, and switching to lower-carbon fuels. Low-cost climate mitigation options, i.e., those costing $100 per tCO2e or less, could halve global GHG emissions by 2030. The long-term benefits of limiting warming would greatly outweigh the costs.
- Clean energy needs to be scaled up. In industries and heavy duty transport, where electrification would be difficult, alternative energy carriers such as hydrogen and ammonia must substitute for fossil fuels.
- Intensive innovation efforts must be taken up to decarbonise industry. Switching to new low- and zero-emission industrial processes is necessary in the production of materials like steel, cement, plastic, pulp and paper, and chemicals.
- Green buildings need to be incentivised. The way ahead is to adopt electric heating, more efficient appliances and lighting, and the circular use of materials. Efforts to retrofit older buildings should be accelerated.
- A shift should be made to low carbon transport. Battery-electric vehicles and electric railways charged by clean power must continue to be encouraged. Advanced biofuels and synthetic fuels should be encouraged with financial and policy support to replace conventional fuel in transport systems like shipping and aviation which are difficult to decarbonise.
- Ecosystems must be conserved and food systems improved. Protecting, restoring, and sustainably managing carbon-rich ecosystems besides reducing the GHG intensity of food production, curbing food waste, and shifting to more sustainable diets will help. Conversion of ecosystem needs to be reduced as deforestation on its own accounts for 45 per cent of emissions from the land sector.
- Lifestyle changes have a crucial role in mitigating climate change. It is the households with incomes in the top decile, most of which are in developed countries, which are responsible for 36–45 per cent of total GHG emissions, while those families in the bottom 50 per cent of earnings account for a mere 13–15 per cent GHG emissions. Changing consumption patterns, particularly among the world’s wealthiest, can bring down GHG emissions by 40–70 per cent by 2050. Some of the most effective demand-side mitigation processes are walking or cycling, avoiding long-haul flights, shifting to plant-based diets, reducing food waste, and using energy more efficiently in buildings. On a unit costs basis, solar energy has dropped 85 per cent, wind by 55 per cent, and lithium-ion batteries by 85 per cent since 2010. Their usage has increased 10 times for solar and 100 times for electric vehicles. This has been possible because of “public R&D, funding for demonstration and pilot projects, and demand-pull instruments such as deployment subsidies to attain scale”. Policies should be devised to help make these shifts in lifestyle easy: low-emission technologies could be subsidised and high emission technologies taxed more, and setting standards to mandate better energy efficiency. Sustainable options should be offered to people, for example, by including vegetarian dishes among meat dishes on menus instead of having them in separate sections. In other words, consumption of plant-based food items should be increased.
- Carbon removal is essential for limiting temperature rise. The readily available and cost-effective approach for carbon removal is to restore natural carbon sinks like forests. In the long term, carbon removal technologies with minimal risks must be developed. Research and development have to be adequately financed.
- The gap between current levels of climate finance and what is required to mitigate climate change, a gap which is widest in developing countries, needs to be closed. Climate finance needs to be some 3 to 6 times higher by 2030 if warming is to be limited to below 2 °C.
How the Report Matters for India
The report’s warning against the opening of new coal plants has to be taken seriously by India. India is reported to have about 211 GW of operational coal-fired power plants, which accounts for some 10 per cent of global capacity. More coal plants are under construction. These plants do not have carbon capture and store (CCS) technology, and the report says that plants without CCS need to be closed by 2050 if global temperature rise is to be limited to 1.5 °C. India is committed to net-zero carbon dioxide emission by 2070. It has set forward a plan to shift to renewable energy sources. However, it has also asserted that it cannot give up its right to use coal for developmental needs. It has pointed out that the developed countries, historically responsible for climate change, should bear a greater burden of the mitigating efforts and shift from fossil fuels.
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