The frequencies of extreme El Nino and La Nina events are the Pacific Ocean is likely to increase in the coming years that could possibly result in more intense wet or dry periods in India, a new report by Intergovernmental Panel on Climate Change (IPCC) said on Wednesday.
‘The Special Report on the Ocean and Cryosphere in a Changing Climate’ is the last in a series of three reports on specific themes that IPCC has published in the last one year. In October last year, it published a report on the feasibility of restricting global rise in temperatures to within 1.5 degree Celsius from pre-industrial times. It was followed by a report on land and climate change last month.
The report released Wednesday takes a look at the impact of climate change on oceans and snow-covered land areas. The report says global mean sea-level had increased by 16 cm between 1902 and 2015, and that the rate of increase had doubled of late. Between 2006 and 2015, global mean sea level recorded an average rise of 3.6 mm per year, which was more than double of 1.4 mm per year recorded in the first 90-year-period of the 20th century.
The melting of glaciers had contributed significantly to the rise in sea-levels, the report says. Between 2006 and 2015, the Greenland ice sheet lost ice-mass at an average rate of 278 billion tonnes every year, which was enough to result in a global sea-level rise of 0.8 mm per year. During the same period, the Antarctic ice sheet lost a mass of 155 billion tonnes on an average every year. Snow over outside of these two regions, like the glaciers in the Himalayas, together lost an average of 220 billion tonnes of ice every year.
Info global, not region specific
Like the other reports of IPCC, this report only gives global information and no region-specific impacts. IPCC also prepares the more comprehensive state of the climate reports, which are simply called Assessment Reports. Five of these have so far been published. The fourth one, which came out in 2007, won it the Nobel Peace Prize. The sixth Assessment Report is due to be published in 2022. That is also supposed to contain region-wise impacts of climate change.
“The sum of ice sheet and glacier contributions over the year 2006-2015 is the dominant source of sea-level rise, exceeding the effect of thermal expansion of ocean water (due to rising temperatures)… Sea-level rise is not globally uniform and varies regionally. Regional differences, within 30 per cent of global mean sea-level rise, result from land ice loss and variations in ocean warming and circulation,” the report says.
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“Since the mid-20th century, the shrinking cryosphere in the Arctic and high-mountain areas has led to predominantly negative impacts on food security, water resources, water quality, livelihoods, health and well-being, infrastructure, transportation, tourism and recreation, as well as culture of human societies, particularly for Indigenous peoples,” it says.
El Nino refers to an abnormal sea-surface warming in certain areas of equatorial Pacific Ocean, off the western coast of South America. La Nina is the opposite phenomenon, an abnormal cooling of sea-surface. Together these events influence weather events worldwide.