Limiting global warming to 1.5 degrees Celsius would require rapid, far-reaching and unprecedented changes in all aspects of society, the IPCC said in a new assessment made public on Monday.
With clear benefits to people and natural ecosystems, limiting global warming to 1.5 degrees compared to two degrees could go hand in hand with ensuring a more sustainable and equitable society, the Intergovernmental Panel on Climate Change (IPCC) said.
The Special Report on Global Warming of 1.5 degrees Celsius was approved by the IPCC -- the UN body for assessing the science related to climate change -- on Saturday in this Korean city.
It will be a key scientific input into the Katowice Climate Change Conference (COP24) in Poland in December, when 195 nations review the 2015 Paris Climate Change Agreement to tackle climate change.
"With more than 6,000 scientific references cited and the dedicated contribution of thousands of expert and government reviewers worldwide, this important report testifies to the breadth and policy relevance of the IPCC," panel chair Hoesung Lee said.
Ninety-one authors and review editors from 40 countries prepared the IPCC report in response to an invitation from the UN Framework Convention on Climate Change (UNFCCC) when it adopted the Paris Agreement in 2015.
'Global Warming of 1.5 oC', the IPCC special report talks the impacts of global warming of 1.5 degrees Celsius above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.
"One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of one degrees Celsius of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes," said IPCC Working Group I Co-Chair Panmao Zhai.
The report highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5 degrees Celsius compared to two degrees, or more.
For instance, by 2100, global sea level rise would be 10 cm lower with global warming of 1.5 degrees Celsius compared with two degrees.
The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5 degrees Celsius, compared with at least once per decade with two degrees Celsius.
Coral reefs would decline by 70-90 per cent with global warming of 1.5 degrees Celsius, whereas virtually all (> 99 per cent) would be lost with two degrees.
"Every extra bit of warming matters, especially since warming of 1.5 degrees Celsius or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems," said IPCC Working Group II Co-Chair Hans-Otto PArtner in a statement.
Limiting global warming would also give people and ecosystems more room to adapt and remain below relevant risk thresholds, added PArtner.
The report also examines pathways available to limit warming to 1.5 degrees Celsius, what it would take to achieve them and what the consequences could be.
"The good news is that some of the kinds of actions that would be needed to limit global warming to 1.5 degrees Celsius are already underway around the world, but they would need to accelerate," said Working Group I Co-Chair Valerie Masson-Delmotte.
The report finds that limiting global warming to 1.5 degrees Celsius would require "rapid and far-reaching" transitions in land, energy, industry, buildings, transport, and cities.
Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 per cent from 2010 levels by 2030, reaching anet zero' around 2050.
This means that any remaining emissions would need to be balanced by removing CO2 from the air.
The IPCC is the leading world body for assessing the science related to climate change, its impacts and potential future risks, and possible response options.
The report was prepared under the scientific leadership of all three IPCC working groups.
Working Group I assesses the physical science basis of climate change; Working Group II addresses impacts, adaptation and vulnerability; and Working Group III deals with the mitigation of climate change.
The Paris Agreement adopted by 195 nations at the 21st Conference of the Parties (COP21) to the UNFCCC in December 2015 included the aim of strengthening the global response to the threat of climate change by "holding the increase in the global average temperature to well below two degrees Celsius above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees above pre-industrial levels".
--IANS
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