The world has an onerous task of reducing human-induced carbon dioxide emissions by 45 per cent of the 2010 levels by 2030, and further to ‘net-zero’ by 2050, to make sure the impact of global warming is minimal, said UN climate agency in a report published on Monday.
The report, adopted by the Intergovernmental Panel on Climate Change at its meeting in Incheon in South Korea on Saturday, stressed the need for limiting global warming to 1.5°C, rather than 2°C , over pre-industrial era levels by 2100. The special report will be a key input when governments meet in December in Katowice in Poland to discuss ways to tackle climate change.
“The longer the delay in reducing CO2 emissions towards zero, the larger the likelihood of exceeding 1.5°C,” the scientists said in the report. It said limiting global warming to 1.5°C will require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities.
The report said 2017 had already witnessed human-induced warming touching nearly 1°C, leaving scope for it to rise a maximum of 0.5°C by the end of the century. One strong message from the report — authored by 91 scientists with expertise in a wide range of scientific subjects — is that the world is already bearing the brunt of climate change with different regions regularly experiencing severe heat waves, droughts and extreme rainfall, leading to flash floods.
“Every extra bit of warming matters, especially since warming of 1.5ºC or more increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems,” said Hans-Otto Pörtner, co-chair of one of the IPCC working groups.
Wake-up call for India
“By 2100, the global sea level rise will be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an Arctic Ocean free of sea ice in summer will be once per century. Coral reefs will decline by 70-90 per cent with global warming of 1.5°C, whereas virtually all of them will be lost with 2ºC,” the IPCC report said. “Even at a little over 1°C warming, India is being battered by extreme climate conditions; clearly, the situation at 1.5°C is going to worsen... we must get our act together — now and quickly,” said Sunita Narain, Director-General, Centre for Science and Environment.
“It is very difficult — but not impossible — to remain within 1.5°C by the end of the century,” she said, adding that the US is the biggest obstacle to forming a global coalition to fight climate change.
The IPCC estimates that to ensure global warming is restricted to 1.5°C, the world has to remove 100-1,000 gigatonne of CO2 over the 21st century..
It is said that by 2050, renewables such as hydro, solar, wind and bioenergy should supply half to two-thirds of all primary energy used globally, with coal’s coming down to 1-7 per cent. From 2020 to 2050, primary energy supplied by oil has to be reduced by 32-74 per cent and natural gas by 13-60 per cent.