India’s first ever national forecast on the impact of global warming on the subcontinent in the coming century, expects annual rainfall to increase, along with more severe cyclones and — paradoxically — more droughts.
These projections, based on a climate forecasting model developed at the Indian Institute of Tropical Meteorology (IITM), Pune, will be part of the next report of the Intergovernmental Panel on Climate Change (IPCC), expected to be ready in 2022.
What does the report say?
The report ‘Assessment of Climate Change over the Indian region’ says that from 1986-2015, the hottest day and coldest night have warmed 0.63°C and 0.4°C, respectively.
By the end of the 21st century, the report says, these temperatures are projected to rise by approximately 4.7°C and 5.5°C, respectively, relative to the corresponding temperatures in 1976-2005. This under a hypothetical scenario where no steps are taken to curb global greenhouse gas emissions or the RCP 8.5 as it is called. Currently countries have signed an agreement to reduce emissions to restrict global temperature rise by the end of the century to less than 2°C.
RCP8.5 is the worst-case scenario used by climate modellers worldwide. In a medium GHG emissions scenario, called RCP4.5, average temperature in India would rise by 2.7 degrees in the last three decades of this century.
The frequencies of future warm days and warm nights are projected to increase by 55% and 70%, respectively, relative to the reference period of 1976-2005. Summer heat waves over India are projected to be three to four times higher by the end of the 21st century.
The projected rapid changes in India’s climate will place increasing stress on the country’s natural ecosystems, agricultural output, and fresh water resources, the report says.
There has been observed a change of 0.7°C in average temperatures over India which has already registered a spike in extreme weather events over the region.
Impact of climate change on India
On Himalayas – The IITM experts have calculated that the Hindu Kush Himalayas (HKH) experienced a temperature rise of about 1.3 degrees between 1951 and 2014. Several areas of HKH have experienced a declining trend in snowfall and also retreat of glaciers in recent decades, though some glaciers in the high-elevation Karakoram range has escaped this retreat due to more winter snowfall. By the end of the twenty-first century, the annual mean surface temperature over HKH is projected to increase by about 5.2 degrees Celsius under the RCP8.5 scenario.
On Monsoon – Sea surface temperature (SST) of the tropical Indian Ocean has risen by 1 degrees Celsius on average during 1951–2015, markedly higher than the global average SST warming of 0.7 degrees Celsius, over the same period. The summer monsoon precipitation (June to September) over India has declined by around 6% from 1951 to 2015, with notable decreases over the Indo-Gangetic Plains and the Western Ghats. There has been a shift in the recent period toward more frequent dry spells (27% higher during 1981–2011 relative to 1951–1980) and more intense wet spells during the summer monsoon season. Over central India, the frequency of daily precipitation extremes with rainfall intensities exceeding 150 mm per day increased by about 75% during 1950–2015.” The report predicts an increase in this variability.
On Land and Sea – The report records that around India, the sea has risen 3.3 mm per year between 1993 and 2017. The scientists forecast that even in an RCP4.5 scenario, by the end of the century the seas around India will rise by 300 mm from the average level between 1986 and 2005. This means a larger area along the coast will be affected by storms and saltwater intrusion.
What should be done?
As per the report, the points of action include “passive reduction of indoor temperatures, water conservation and rainwater harvesting, groundwater regulation, reversing land degradation, reduction in food and water wastage, waste segregation and recycling, low impact urban development, expansion of urban green spaces and urban farming, pollution control, increasing the area under irrigation and improving the efficiency of agricultural water use, forest conservation and proactive afforestation, construction of coastal embankments and mangrove restoration, improvement in disaster response, phasing out fossil fuels and transition to renewables, electrification, expansion of walking, bicycling and public transport infrastructure, and carbon taxation.”
Overall, climate change has already made India hotter and drier since the middle of the twentieth century, with more droughts, cloudbursts, floods, rising seas, stronger cyclones and a change in the monsoon pattern.
World Day to Combat Desertification and Drought
World Day to Combat Desertification and Drought is being observed on June 17, 2020 with the theme “Food. Feed. Fibre – the links between consumption and land”.