Profile picture
Chris Mooney @chriscmooney
, 18 tweets, 3 min read Read on Twitter
1. I was busy yesterday with the very big news that global carbon emissions went up again this year – fast. As a result, I missed a quite important and -- as we’ll see – related piece of new research. washingtonpost.com/energy-environ…
2. This was the finding that the surface melting of Greenland is at higher levels than at any time in the last 350 years, and is showing a “nonlinear” response to rising temperatures. Study in Nature here. nature.com/articles/s4158…
3. Greenland is the world’s second largest ice sheet, and currently the biggest ice loser among them. It contains 20 feet or more of potential sea level rise, and is already raising seas every year by close to a millimeter sealevel.nasa.gov
4. In the new research, scientists used ice cores pulled from the Greenland ice sheet to show that there hasn’t been anything like present day surface melting in the past several centuries.
5. “Our results show a pronounced 250% to 575 % increase in melt intensity over the last 20 years, relative to a pre-industrial baseline period,” for one of the ice cores, they write.
6. The fast-rising melt rate also seems tied to the shrinkage of Arctic sea ice, atmospheric changes and, perhaps, a slowing of the Atlantic ocean’s overturning circulation.
7. But the most important part of the research is probably the finding that this is “a clear non-linear melt-temperature relationship.” In other words, as temperatures go up, the rate of Greenland melting doesn’t tick up at the same pace. It goes up faster.
8. This is the kind of process that could lead to a significantly higher rate of sea level rise.
9. The researchers conclude that “only limited additional warming will greatly enhance the area of the ice sheet subject to meltwater runoff.”
10. Some parts of the ice sheet are at very high elevations and quite cold – or have been. The study is saying that they could be next if warming continues, and it won’t take much.
11.What the research may imply but doesn’t quite say – this would take another study – is whether this means we should expect more sea level rise out of Greenland during this century than previously predicted. (Greenland is currently the world’s top sea level rise driver.)
12.However, the study should be weighed in light of yesterday’s news that the world still can’t stop the growth of its carbon emissions.
13. We have a decade or so bring them down fast to limit warming to only another half a degree Celsius. And according to the latest research, even such “limited additional warming” could “greatly enhance” Greenland’s melting.
14.The point is, you probably don’t want to go past another .5C of warming if you have a nonlinear response in a system like the melting of Greenland. (Not that it’s the only one.)
15.Indeed, the recent IPCC 1.5 degrees report found: “Instabilities exist for both the Greenland and Antarctic ice sheets, which could result in multi-meter rises in sea level on time scales of century to millennia.... "
16. "...There is medium confidence that these instabilities could be triggered at around 1.5°C to 2°C of global warming.” ipcc.ch/site/assets/up…
17. Thus, the recent Greenland research, and the recent carbon emissions research, could be interpreted jointly to mean the following:
18. If the world doesn’t reach a peak in its emissions fast, and then get them going down rapidly, the science suggests we are risking even bigger changes than we’ve seen so far to the Earth’s second biggest ice sheet. /end
Missing some Tweet in this thread?
You can try to force a refresh.

Like this thread? Get email updates or save it to PDF!

Subscribe to Chris Mooney
Profile picture

Get real-time email alerts when new unrolls are available from this author!

This content may be removed anytime!

Twitter may remove this content at anytime, convert it as a PDF, save and print for later use!

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just three indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member and get exclusive features!

Premium member ($30.00/year)

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Try unrolling a thread yourself!

how to unroll video

1) Follow Thread Reader App on Twitter so you can easily mention us!

2) Go to a Twitter thread (series of Tweets by the same owner) and mention us with a keyword "unroll" @threadreaderapp unroll

You can practice here first or read more on our help page!

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just three indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member and get exclusive features!

Premium member ($30.00/year)

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!