Global climate change is likely to result in severe droughts and floods in the world’s biggest democracy, with major impacts on human health and food supplies, according to India’s report to the United Nations Framework Convention on Climate Change.
And India is not alone, according to other reports available on the Science and Development Network. An earlier UN report from Namibia predicts “extreme” impacts on water, fish stocks and agriculture in Southern Africa, resulting in economic hardship, food security problems, social conflict, displacement and increased disease.
By drying up major river basins and altering rainfall patterns, global warming will significantly affect agriculture and forestry, threatening livelihoods and food security, says the latest report, released by India’s new Environment Minister, A Raja.
The report predicts that maximum temperatures will increase by two to four degrees Celsius over the next 50 years, with northern India expected to experience the greatest increase. This corresponds with claims made earlier this year by scientists at the Indian Institute of Tropical Meteorology in Pune, who predicted “phenomenal” temperature increases.
Rainfall patterns are also set to change. Western and central areas could have up to 15 more dry days each year, while in contrast, the north and north-east are predicted to have five to 10 more days of rain annually. In other words, dry areas will get drier and wet areas wetter.
The report predicts that the area of India prone to malaria will increase by at least 10% by 2080, as changing weather patterns will result in more potential breeding grounds for malarial mosquitoes at higher altitudes.
Most major river basins across the country are likely to become considerably drier, resulting in constant water shortages that will occasionally become acute, the report says. This could shift forest boundaries and affect biodiversity in the regions affected.
In coastal areas, the key climate-related risks include more frequent tropical cyclones and rises in sea level that will submerge mangrove forests and increase the salinity of wetlands. According to the report, if sea levels were to rise by 1m, more than seven million people in India could be displaced and more than 5Â 000 square kilometres of land and 4Â 000 kilometres of roads could be lost.
Despite the diversity and extent of threats posed to India by climate change, the report says Indian emissions of greenhouse gases have been “very low”. According to Raja, this strengthens India’s negotiating position in various climate change forums.
Speaking at the release of the report, he said that India will continue to meet its development needs but is concerned about the likely impact of severe floods on its infrastructure such as roads and railways, as well as the likely increase in electricity needs to pump underground water and cool houses and offices in hot areas.
Earlier this year, scientists at the Pune-based Indian Institute of Tropical Meteorology (IITM) used two models to forecast the impact of global warming.
Both models predict that the country’s temperatures will rise significantly until the end of the century. But the two models differ on the effect on monsoon rains.
One global climate model predicts that temperatures in India are likely to rise by two to three degrees Celsius by the end of the century if greenhouse gas concentrations increase by 1% each year.
Rupa Kumar Kolli, head of the institute’s climatology and hydrometeorology division, who presented the findings at the Indian Science Congress in Chandigarh, said the increase could have serious consequences for crop growth and weather patterns, given that India’s temperature has risen by only 0,4 to 0,6 degrees Celsius over the past century.
The other model — a high-resolution regional climate model developed under joint Indo-United Kingdom collaboration — also projects a general warming over India. The IITM team has yet to run the regional model up to the end of the century, but an analysis up to 2050 indicates a temperature rise of between one and two degrees Celsius, in line with estimates of the global model.
The two models, however, come up with different conclusions about the impact of global warming on India’s monsoon rainfall — the most crucial weather element that is the lifeline to the country’s agriculture and central to the livelihoods of 70% of the country’s population.
The global model predicts a 10% increase in monsoon rainfall over the next century. In contrast the regional model predicts that rainfall will remain at current levels up to 2050.
Both models indicate a weakening of the link between El Niño, the warming of eastern Pacific waters that affects global weather patterns, and the monsoon. Kolli says the weaker link has already been evident in India over the past two decades.
“This is now being considered an early signal of possible global warming effect on monsoon variability,” he says.
Global warming, however, is not expected to affect the link between La Niña, or the cold sea-surface temperatures in tropical Pacific waters, and the Indian monsoon.
The institute is also running the regional model against 10 to 15 scenarios based on differing patterns of human behaviour that are likely to lead to an increase in the use of fossil fuels and concentrations of greenhouse gases and aerosols.
While greenhouse gases such as oxides of carbon, nitrogen and sulphur increase atmospheric temperatures by trapping heat, aerosols — tiny atmospheric particles produced naturally through volcanic eruptions, dust storms and fires, or through human activities such as fossil-fuel burning — cool the air by scattering and blocking the sun’s radiation to the Earth.
Large cities in India and China are recording an “alarming” increase in aerosols due to human activities, creating “hot spots” for climate change, warns A Jayaraman from the Ahmedabad-based Physical Research Laboratory, which is studying the likely impact of aerosols on India’s climate. — SciDev.Net