Latest NASA global temperature data.
Earth has never been hotter since Homo sapiens discovered agriculture in the early Holocene. Likely even since 120,000 years ago.
Fossil coal, oil and gas emissions caused it.
We need to stop making it worse.
Yes, we can if we want to. 🧵
Here is the last 2023 years of data for CO2 (from Antarctic ice core data) and global temperature (from numerous sources of proxy data from around the world, such as sediment and ice cores). Check it out: pastglobalchanges.org/science/wg/2k-…
And here's global temperature for the past 24,000 years - since the last Ice Age! Earth is now warming 20 times faster than at the end of the last Ice Age.
(Ice ages are caused by the Earth orbit's Milankovich cycles - modern warming is not.)
Source: nature.com/articles/s4158…
And it is Physics 101 that the atmospheric „sponge“ (capacity to hold & move around water) grows exponentially with warming.
(Clausius-Clapeyron law, known since 1834.)
Hence the air sucks more water from soil & plants & seas in dry weather, and pours out more extreme rainfall.
Even over time periods of hundreds of millions of years, where it’s plate tectonics which changes atmospheric CO2 levels, CO2 is the main control knob for global temperature.
Homo sapiens emerged only around 300,000 years ago in Africa.
Should anyone be interested in the usual selection of well-worn „climate skeptics“ claims that undoubtedly will appear in the comments, they are all already covered here:
I was shocked when I first saw these results from standard climate models used in IPCC reports:
for high emissions, the Atlantic overturning circulation #AMOC shuts down in all 9 models that ran
past 2100, and is well on the way to shutdown by 2100.
Our paper is out today. 🧵
The latest climate model generation CMIP6 consists of models from institutes around the world.
The IPCC report found that the crucial Atlantic Ocean circulation #AMOC will weaken. Now
some of the models have been continued beyond year 2100 and reveal a high risk of full
shutdown.
Even more worrying: the tipping point where the shutdown becomes inevitable appears to be
when deep convection in the northern Atlantic stops. This tends to happen in the next few
decades in these models, see two examples. Despite the models not even including Greenland
ice loss!
We see here a self-styled "honest broker" with decades of experience in downplaying climate change presenting an age-old climate denial trope: using *annual* rainfall data as argument against an increase in *extreme* rainfall.
Does he *really* not know better?
Brief 🧵1/4
What scientists have predicted since the 1980s is an increase in heavy rain at the expense of days with light or no precipitation. And that is indeed observed. See @Knutti_ETH That is because warmer air can hold more moisture (Clausius-Clapeyron law). 2/4 nature.com/articles/nclim…
That means an air mass saturated with water will hold 7% more water per degree of warming, so 7% more can rain out, all else remaining the same. Heavy rain gets that much stronger.
Why doesn't that apply to annual rainfall totals? Because those are ruled by different physics. 3/4
1. Extreme rainfall increases as global temperatures rise.
There’s a basic law of physics behind that (Clausius Claperon Law, known since 1834, see Wikipedia).
And numerous analyses of weather station data prove it. See e.g. ours. nature.com/articles/s4161…
2. Global warming is caused by fossil fuel emissions. That is why it was predicted correctly before it was even observed. And even by scientists from fossil fuel companies like Exxon Mobil. But their bosses decided to tell you a different story.
A new study by van Westen et al. shows that the #tippingpoint of the Atlantic overturning circulation #AMOC is also found in a high-resolution ocean model which resolves ocean eddies. A first, but no surprise to AMOC experts. 🧵
To find the tipping point you need to do a very slow, long hysteresis model run. That is so computationally expensive that it hasn't been tried before. All models which have tried show this tipping point - we published a first intercomparison in 2005. 🧵 agupubs.onlinelibrary.wiley.com/doi/10.1029/20…
So all kind of models since Stommel's 1961 box model show it, due to the destabilising salt transport feedback. The new model also shows the well-known sea surface temperature fingerprint pattern of an #AMOC shutdown: the 'cold blob', and warming along the American coast. 🧵
Zur Erinnerung: Kernfusion ist /keine/ Klimalösung sondern klimaschädlich. (Nur falls jemand auf die Idee kommt, diese Träume von Merz mit Klimaschutzgeldern zu subventionieren.)
Kurzer Thread in 5 Bildern.
2024 war global das heißeste Jahr seit Beginn der Aufzeichnungen, mit 1,6 Grad über dem Temperaturniveau des späten 19. Jahrhunderts. Kleiner Thread mit Datengrafiken dazu. 🧵
In Deutschland war es ebenfalls das wärmste Jahr seit Beginn der Aufzeichnungen - allerdings schon 3,1 Grad wärmer. Weil Deutschland ein Landgebiet ist, erwärmt es sich doppelt so schnell wie der globale Mittelwert, der 71% Meeresfläche enthält. 🧵
Diese moderne Erderwärmung ist praktisch komplett vom Menschen verursacht. Natürliche Faktoren haben weniger als + oder - 0,1 °C beigetragen. Das ist eine Kernaussage des Weltklimarats IPCC. Eher - als +, weil die Sonnenaktivität etwas abgenommen hat. 🧵