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37 things you need to know

about 1.5C global warming

By Megan Darby and Sara Stefanini for Climate Home News

The UN climate science panel has released its summary of the evidence around the
tougher climate goal demanded by vulnerable countries. We break it down.

The UN published a summary on the science of 1.5C global 1. The first draft summary circulated for review in January
warming in October. It’s a big deal. included a high-level statement. That disappeared from
subsequent versions, which is a shame because it helped to
This is the first time the Intergovernmental Panel on Climate
Change (IPCC) has gathered evidence on the tougher target clarify the findings. It is a sign of how politically sensitive the
demanded by countries on the front line of climate impacts. issues are that governments did not agree on which elements
to highlight.
It validates their concerns, showing that the difference between Understanding 1.5C warming
1.5C and 2C – the upper limit governments committed to in the 2. The world has already warmed by 1C since pre-industrial
Paris Agreement – is critical to millions of people’s homes, jobs times, due to human activity. On current trends, it is likely
and lives.
to pass the 1.5C mark between 2030 and 2052. The land is
As to whether it is feasible to halt the temperature rise at 1.5C warming faster than the oceans and the Arctic is warming at
above pre-industrial levels, the report has no easy answers. What 2-3 times the global average rate.
it does is elucidate the options.
3. There is a time lag between greenhouse gas emissions and
It was a mammoth undertaking, with 91 authors from 40 their effect on the climate. That means the world is already
countries compiling evidence from more than 6,000 papers and committed to further warming and sea level rise, but past
addressing 42,001 comments from experts and governments. emissions are unlikely to tip temperatures over the 1.5C
In a tense meeting in South Korea, government representatives threshold.
haggled with scientists for six days to produce a 33-page summary 4. To stabilise temperatures, emissions need to reach net zero
of four in-depth chapters. and stay there. That means cutting emissions as much as
The result of writing by committee is a somewhat dense and possible and drawing carbon dioxide out of the air to balance
technical document. Here is our breakdown of the key messages out any remaining emissions. The amount of warming is
and omissions, and their political significance. ultimately determined by how long it takes to get to net zero.

Ilulissat fjord, Greenland: Arctic temperatures are rising faster than the global average (Photo credit: Wikimedia, Ranveig Thattai)

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