UN report on climate change: 5 things you must know

United Nations, Aug 09: UN Climate panel released a key report on Monday summarising the latest authoritative scientific information on climate change. The report updated governments with up-to-date facts on the current impacts and future risks of global warming ahead of a UN climate summit in November in Glasgow.

Humans to blame

The world is dangerously close to runaway warming and that humans are "unequivocally" to blame, the IPCC used its strongest terms yet to assert that humans are causing climate change.

The report says almost all of the warming that has occurred since pre-industrial times was caused by the release of heat-trapping gases such as carbon dioxide and methane. Much of that is the result of humans burning fossil fuels coal, oil, wood and natural gas.

Scientists say that only a fraction of the temperature rise recorded since the 19th century can have come from natural forces.

Paris goals

Almost all countries have signed up to the 2015 Paris climate accord that aims to limit global warming to 2 degrees Celsius (3.6 Fahrenheit) and ideally no more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) by the year 2100, compared to the late 19th century.

The report's 200-plus authors looked at five scenarios and concluded that all will see the world cross the 1.5-degree threshold in the 2030s sooner than in previous predictions. Three of those scenarios will also see temperatures rise 2 degrees Celsius above the pre-industrial average.

Sea levels

Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century.

Coastal areas will see continued sea level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion with extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century, said the IPCC Working Group I report, which is the first installment of the AR6, to be completed in 2022.

Global warming

It said that for 1.5 degrees Celsius of global warming, there will be increasing heat waves, longer warm seasons and shorter cold seasons. At 2 degrees Celsius of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health.

But it is not just about temperature. Climate change is bringing multiple different changes in different regions which will all increase with further warming. These include changes to wet and dryness, to winds, snow and ice, coastal areas and oceans, it said.

Net zero

If we reduce emissions globally to net zero by 2040 there is still a two-thirds chance to reach 1.5 degrees and if we globally achieve net zero emissions by the middle of the century, there is still a one-third chance to achieve that, said Dr Friederike Otto, Associate Director of the Environmental Change Institute at the University of Oxford and one of the authors of the IPCC report.

with PTI inputs