Steeling myself with a strong coffee to sit down and read major new report on avoiding dangerous #climatechange ( @IPCC_CH #SR15, available here: http://www.ipcc.ch/report/sr15/ ). My takes to follow (1/n)

As always, the #peerreview effort by @IPCC_CH is Herculean. A couple hundred volunteer scientists read & cited 6,000+ studies to support conclusions w/ evidence. Responded to 42,001 comments in 3 rounds of review. The most robust process there is to establish scientific consensus

Now, this #SR15 report title is descriptive, but doesn't exactly roll off the tongue...

Humans have caused 1.0°C warming so far, which will last for 100s to 1000s of years. We have not yet emitted enough to warm 1.5° but are on track to do so w/ current emissions rates as soon as 2030. More warming = more risks. #SR15 headline statements

Limiting warming to 1.5° instead of 2° makes a big & important difference to land and marine species & ecosystems, & the benefits humans derive from nature (fisheries, water supply, food security), human health & security, & economic growth. #SR15 headline statements

#sealevelrise will continue for centuries, but how much and how fast depends on our choices for greenhouse gas emissions going forward. SLR will be 0.1m lower at +1.5° instead of +2°, and rise slower, which enables more possibilities for adaptation. #SR15 headline statements

There are many adaptation options that reduce risk; more options open to us to adapt to #climatechange of +1.5 vs. 2°. However, even at 1.5° there are some unavoidable losses. There are some climate changes humans & nature cannot adapt to. #SR15 headline statements

To limit warming to 1.5°, humans must reduce CO2 & other greenhouse gases by 45% by 2030 (vs 2010 levels). Requires deep, rapid reductions in all sectors (energy, land, urban, transport, buildings, industry). This needs much more investment in mitigation #SR15 headline statements

Limiting warming to 1.5° requires human greenhouse gas emissions to go to ZERO by 2050. Any emissions remaining after 2050 must be removed from the atmosphere to avoid contributing to further warming. #SR15 headline statements

Limiting warming to below 2° requires reducing CO2 20% by 2030 (vs. 2010 level) and to ZERO by 2075 (if any emissions remain then, they must be removed from the atmosphere). #SR15 headline statements (Limiting warming at any given temp requires net zero emissions.)

To limit warming to 1.5°, humans will have to remove some carbon from the atmosphere. This has its own risks. If we reduce emissions fast, we can limit amount of carbon removal needed & avoid relying on bioenergy with carbon capture and storage (BECCS). #SR15 headline statements