The second visual shows how observed warming is driven by emissions from human activities.
It shows that greenhouse gases alone would already have warmed the planet by 1.5°C, but air pollution is currently cooling it. Both need to be tackled.
(4/n)
Climate change is already affecting us our activities contribute to many observed changes in weather and climate extremes.
Each red hexagon represents a world region in which observed hot extremes have increased, with the number of dots representing our confidence.
(6/n)
This visual was actually too large to fully fit in a single tweet. Here is the same visual for heavy precipitation and droughts.
The fourth visual shows scenarios that help @IPCC_CH describe the implications of our emission reduction choices.
They cover a full range from very high emissions that require a roll-back of climate policies to very low emissions that require deep cuts in the next decade. (9/n)
The final visual for today shows that every increment of warming matters for climate impacts.
That is true for temperatures. (10/n)
As well as for precipitation and soil moisture - important for the impact heatwaves have on society and crops.
(11/n)
Enough for today. Stay tuned for the second part of visual over the next days. (end)
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After yesterday, we now landed on changes in extremes🌡️⛈️🥵🧺!
And although I don't like to pick favorites, I do like this visual very much.
Too big for a single tweet, this one shows how hot extremes over land change compared to when our great-grandparents were alive. (2/n)
Did you notice in the previous figure: a heat extreme that our great-grandparents would have experienced once in their lifetime, will occur about once every 4 years in a 2°C warmer world. It will be the norm in a 4°C warmer world.
Carbon budgets tell us how much CO2 we can still emit while keeping warming below specific limits.
The latest @IPCC_CH report provides updated estimates of these budgets.
Here’s an insider's view with a deep dive looking at how they have changed since previous reports. (1/n)
I have been involved in the estimation of carbon budgets since the IPCC Fifth Assessment Report in early 2010s.
And since the first IPCC estimates published in 2013, we have learned a lot and have gotten much better at estimating remaining carbon budgets. (2/n)
The scientific basis underlying a carbon budget is our robust scientific understanding that global warming is near-linearly proportional to the total amount of CO2 we ever emit as a society.
This is shown in Fig. SPM10, both for the past and future projections. (3/n)
EXPLAINER: new projections for the next 5 years by @metoffice and @WMO indicate that there's a high chance that one of these years is 1.5°C warmer than average preindustrial levels.
The 1.5C level in the @metoffice announcement should not be confused with the 1.5C limit in the Paris Agreement.
The Paris targets refer to global warming - that is, the temperature increase of our planet once we smooth out important year-to-year variations (see👇)
(2/n)
Even in a stable climate, global temperatures differ from year to year because of noise in the climate system.
A detailed look at the report shows that @IEA has done a thorough job.
Modelling choices underpinning the pathway are well argued, reliance on speculative technologies is limited, and the carbon budget is in line with the most ambitious pathways available in the literature (2/n)
In addition, the report also presents a unique collaboration between two of the core flagship teams of @IEA: The World Energy Outlook and the Energy Technology Perspectives.
The @Science_Academy's analysis starts from carbon budgets reported in @IPCC_CH's 1.5°C Special Report's Table 2.2 (orig. below).
Then makes adjustments & updates.
Having had the pleasure to compile Table 2.2 for #SR15, let's compare and try to make sense of the numbers
(2/n)
The @Science_Academy's table starts from IPCC's 1.5C carbon budget for a 50% chance.
(Note1: the table quotes either a wrong likelihood or a wrong number, but that's a detail)
(Note2: IPCC Table 2.2 is in GtCO2, the table below in GtC. Multiply by 3.6 to convert to GtCO2)