Context:
- The IPCC has issued arguably its strongest warning yet on impending catastrophe from unmitigated global warming caused by human activity, lending scientific credence to the argument that rising wildfires, heatwaves, extreme rainfall and floods witnessed in recent times are all strongly influenced by a changing climate.
Relevance:
- GS Paper 3: Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.
Mains Questions:
- IPCC’s warning on climate points to a small window of opportunity that still exists. Discuss. 15 Marks
Dimensions of the Article:
- About Intergovernmental Panel on Climate Change report
- Changes of climate change in Indian Region
- Way Forward
About Intergovernmental Panel on Climate Change report:
- In a stark report on the physical science basis of climate change contributed for a broader Assessment Report of the UN, the IPCC’s Working Group I has called for deep cuts to carbon dioxide emissions and other greenhouse gases and a move to net zero emissions, as the world would otherwise exceed 1.5°C and 2°C of warming during the 21st century with permanent consequences.
- Climate change is described by many as a far greater threat to humanity than COVID-19, because of its irreversible impacts.
- The new report attributes catastrophic events to sustained global warming, particularly the frequency and intensity of hot extremes, marine heatwaves, heavy precipitation, agricultural and ecological droughts, proportion of intense tropical cyclones, reductions in Arctic Sea ice, snow cover and permafrost.
- A phenomenon such as heavy rainfall over land, for instance, could be 10.5% wetter in a world warmer by 1.5°C, and occur 1.5 times more often, compared to the 1850-1900 period.
- In 2018, the Intergovernmental Panel on Climate Change (IPCC) Special Report on Global Warming of 1.5°C (IPCC SR 1.5°C) warned that the impacts of warming at 2°C would be significantly worse than those at 1.5°C.
- According to IPCC SR 1.5°C, to avoid or limit any overshoot of the 1.5°C temperature goal, CO2 emissions will need to be phased out almost entirely by 2050.
- Human-induced global warming has in 2017 already reached 1°C above preindustrial levels; the current climate efforts of countries will take the world to 1.5°C between 2030 and 2052.
Changes in Climate in the Indian region
India is a vast country with many climate zones. The regional climate over the Indian subcontinent involves complex interactions of the atmosphere–ocean– land–cryosphere system on different space and time scales. In addition, anthropogenic activities have influenced the regional climate in recent decades. In a first ever attempt to document and assess climate change in different parts of India, Ministry of Earth Sciences’ (MoES) has come up with the report titled ‘Assessment of Climate Change over the Indian Region’. As per the report, following are the observed and projected changes in various climatic dimensions over the Indian region:
Temperature Rise:
- India’s average temperature has risen by around 0.7°C during 1901–2018
- By the end of the twenty-first century, relative to the recent past (1976–2005 average) it is projected:
- Average temperatures to rise by approximately 4.4°C.
- frequency of summer (April–June) heat waves over India is projected to be 3 to 4 times higher.
- Amplification of heat stress is expected across India, particularly over the IndoGangetic and Indus river basins.
- Causes: The surface air temperature changes over India are attributed mostly by greenhouse gases and partially offset by other anthropogenic forcing including aerosols and Land Use Land Cover LULC change.
Sea-level rise in the North Indian Ocean (NIO):
- While, the major contribution to global mean sea-level rise is from glacier melt, thermal expansion (thermosteric) has dominated sea-level rise in the NIO. The NIO rose at a rate of 3.3 mm year during 1993–2017 against a rate of 1.06–1.75 mm per year during 1874–2004. The water along India’s coasts is expected to rise by 20-30 cm by 2100.
- Sea Surface Temperature: SST of the tropical Indian Ocean has risen by 1°C on average during 1951–2015, markedly higher than the global average SST warming of 0.7°C.
- Causes: Sea-level rise of the NIO during the recent 3–4 decades are closely linked to the weakening trend of summer monsoon winds and the associated slowdown of heat transport out of the NIO.
Change in Rainfall pattern:
- Summer monsoon rainfall (June to September) over India which contribute to more than 75% of the annual rainfall has declined by 6% between 1951-2015 especially in the densely populated Indo-Gangetic plains and the Western Ghats.
- The frequency of localized heavy rain occurrences has significantly increased by 75% during 1950–2015.
- Monsoon onset dates are likely to be early or not to change much, and the monsoon retreat dates are likely to be delayed, resulting in lengthening of the monsoon season.
- Causes: Global-scale anthropogenic forcing such as GHGs as well as regional-scale forcing such as aerosols and LULC changes i.e. increasing urbanisation.
Floods
- Flooding events over India have also increased since 1950, in part due to enhanced occurrence of localized, short-duration intense rainfall events.
- 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.
Droughts:
- The area affected by drought has increased by 1.3% per decade over the the last 6–7 decades.
- Climate model projections indicate a high likelihood of increase in the frequency (>2 events per decade), intensity and area under drought conditions in India by the end of the twenty-first century.
- Causes: increased variability of monsoon precipitation and increased water vapour demand in a warmer atmosphere that tend to decrease soil moisture content.
Tropical Cyclonic Storms:
- The intensity of tropical cyclones (TC) is closely linked to ocean SST and heat content.
- There has been a significant reduction in the annual frequency of tropical cyclones over the NIO basin since the middle of the twentieth century (1951–2018). In contrast, the frequency of very severe cyclonic storms (VSCSs) during the post-monsoon season has increased significantly (+1 event per decade) during the last two decades (2000–2018).
- Climate models project a rise in the intensity of tropical cyclones in the NIO basin during the twenty-first century.
Himalayan Cryosphere:
- The Hindukush Himalayas (HKH) (largest area of permanent ice cover outside the North and South Poles, also known as the ‘Third Pole’) underwent rapid warming at a rate of about 0.2oC per decade during the last 6–7 decades. Higher elevations of the Tibetan Plateau (> 4 km) experienced even stronger warming in a phenomenon alluded to as Elevation Dependent Warming. With continued global warming, the temperature in the HKH is projected to rise by about 5.2°C during the twenty-first century.
- The HKH experienced a significant decline in snowfall and glacial area in the last 4– 5 decades. With continuing warming, climate models project a continuing decline in snowfall over the HKH during the 21st century.
- The Kathmandu-based International Centre for Integrated Mountain Development’s (ICIMOD) “Hindu Kush Himalaya Assessment” reveals that more than one-third of the glaciers in the region could retreat by 2100, even if the global temperature rise is capped at 1.5ºC.
Some other Implications of changing climate over various regions of India
- Food Security: Due to lack of irrigation, a large number of farmers are dependent on monsoon rainfall to practice agriculture (between 50 to 60% of Indian agriculture is rainfed, without access to any form of irrigation).
- Rising temperatures, heat extremes, floods, droughts and increasing year-to-year rainfall variability can disrupt rainfed agricultural food production and adversely impact crop yield. Example- As per the NITI Aayog document, of the total pulses, oilseeds & cotton produced in the country, 80% pulses, 73% oilseeds and 68% cotton come from rain-fed agriculture.
- Ocean warming has reduced the abundance of some fish species by killing parts of the coral reefs they depend on.
- Water security: The growing propensity for droughts & floods because of changing rainfall patterns would be detrimental to surface and groundwater recharge.
- Also, the rising sea level leads to intrusion of saltwater in the coastal aquifers contaminating the ground water. E.g. in Gujarat, Tamil Nadu, and Lakshadweep etc.
- Declining trend in snowfall and retreat of glaciers in HKH region may impact the water supply in the major rivers and streams including the Indus, Ganges, and Brahmaputra \
- Damage to coastal infrastructure
- Potential coastal risks include loss of land due to increased erosion, damage to coastal projects & infrastructure such as buildings, roads, monuments, and power plants, salinization of freshwater supplies and a heightened vulnerability to flooding. Damage to coastal infrastructure.
- For example, higher sea levels and receding coastlines escalate the destructive potential of storm surge associated with cyclonic storms that may be additionally compounded by land subsidence occurring in parts of the country due to factors such as the declining water table depth.
- Social Issues:
- Large scale migration induced due to climatic disasters such as droughts, cyclones and floods cause social distress at the source and destination places. This reflects into unorganised nature of jobs, slums in urban areas and also social tensions.
- According to World Migration Report 2020 released by the UN, Climate change displaced 2.7 million Indians in 2018. Report also highlights that the largest new internal displacements in Asia resulted from disasters.
- Moreover, repeated crop failures add to the burden of already distressed farmers who then resort to suicides.
- Cascading of climatic hazards–
- Multiple negative climate events when acting in tandem could create an extreme situation.
- For instance, a region may experience an abnormally long or intense summer heat wave followed by intense monsoon floods that alternate with lengthening dry spells.
Way Forward
- The new report sets the stage for the CoP26 conference in November. The only one course to adopt there is for developed countries with legacy emissions to effect deep cuts, transfer technology without strings to emerging economies and heavily fund mitigation and adaptation. Developing nations should then have no hesitation in committing themselves to steeper emissions cuts.
