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Did you know that today is ARCTIC SEA ICE day? In its honour, here are a few interesting facts (and some great pictures) courtesy of @PolarBears and @NSIDC (thread) polarbearsinternational.org/get-involved/a…
First, why July 15th? Because ice breakup on Western Hudson Bay occurred around this date historically, marking the beginning of the region's bears' long summer fast. Today, thanks to a rapidly warming Arctic, the breakup is happening ~3 weeks earlier than just 30 years ago. 
We've known since the work of Swedish scientist Svante Arrhenius that, as carbon dioxide from human activities builds up in the atmosphere, the Arctic would warm faster than the rest of the world. Learn more about early climate scientists here:
The Arctic is warming faster due to self-reinforcing cycles, one of which involves sea ice! As sea ice thins and melts, it is replaced with darker water that absorbs more of the sun's energy and makes the region heat up even faster. You can see the difference here:
The @NSIDC tracks sea ice in the Arctic and their website contains many useful graphics including this one, which shows that sea ice this summer is currently tracking that of the lowest year on record, 2012. If it continues, we could set a new record low. nsidc.org/arcticseaicene…
In the US National Climate Assessment, we have a chapter specifically about the Arctic. It also talks about how rising temperatures are causing permafrost to thaw, and how ice loss from Greenland and glaciers continues, in some cases accelerating. science2017.globalchange.gov/chapter/11/
Sea ice is also a key part of the ecosystems in the Arctic (and is important for the native peoples who use it to hunt, too!). Polar bears, seals and more depend on it as key habitat ... habitat whose duration and extent is shrinking quickly.
And finally, in this Global Weirding episode we talk about how what happens in the Arctic doesn't stay in the Arctic - it affects all of us, no matter where we live.
What sea ice fact or figure would you like to add to this thread?
