Post
Predictions of irreversible, unavoidable climate changes
Most people nowadays have a basic understanding of climate change mechanics: Fossil fuels emit CO2, greenhouse effect increases, poles melt, beach resorts disappear. It's a bit more complicated than that, though. All changes aren't foreseen with equal certainty, complex systems biology models are needed to understand feedback mechanisms, some changes might be unavoidable already... and some even irreversible in any foreseeable future.
A team of scientists have taken a step back and summed up on those climatological predictions that are both a) "illustrative", b) adverse, c) irreversible, d) already occuring, e) evidently anthropogenic, f) based on well understood physical principles and g) agreed upon by many models. It includes plenty for worry.
Uncle Ocean has had it with us
While we have emitted CO2 into the atmosphere throughout our time as an industrialized species about 80% of it has actually been absorbed into the ocean. Because the ocean and the atmosphere is exchanging such gasses as CO2, always on the move towards a state of equilibrium. This buffer provided by Earths vast quantities of water has perhaps deluded us into hybris. But now we have emitted so much carbon dioxide the ocean is beginning to slow down its uptake as it is full of it, so to speak. But this is, perhaps, the least of the implications. There is another consequence: If we remove carbon dioxide from the atmosphere, the oceans will slowly start emitting it in stead of absorbing it. Thus, "normalization" will be slow. In the words of the scientists themselves:
"[...] atmospheric temperature increases caused by rising carbon dioxide concentrations are not expected to decrease significantly even if carbon emissions were to completely cease."
In most models (which all assume we do cease emissions soon) only about half the temperature rise is observed while emissions continue; the rest thereafter. The other greenhouse gasses does not show this annoying feature. In this respect, CO2 is unique.
An example of a prediction: a model run with a peak CO2 level of 800 ppm has the level slowly drop to 500 ppm. In year 3000. A bit too slow for me personally.
The two certain changes
Not a long list. But we can count on it.
- The sea level will rise
The most optimist model run in this project (immediate cessation of emissions) has the sea level go up by some 20 cm (about 8 inches) in this century. And even while the carbon dioxide levels are dropping in their painstakingly slow rate the sea levels actually still climb year 3000, although not much. But it goes to show how slow these mechanisms work. And that's from thermal expansion ("swelling" of warmer water) of the ocean alone.
The second factor highlighted is the melting of land ice masses. The complete melt off of these will lead to a sea level rise of 20 to 70 cm. A third is the melting of sea ice - much harder to predict but impossible not to mention due to its incredible worst case scenario consequences. - The sub-tropics will become drier
Patterns of precipitation will change. Exactly how is a complex question to answer involving meteorology as well as climatology. But drying of the sub-tropics is predicted and already happening in manners consistent with previous models. Particularly observed in the well studied southern USA and Mediterranean but also in eastern South America and western Australia.
This drier climate will have other consequences in turn. Dependent on the region ecosystem changes will include loss of drinking water resources, serious effects on agriculture, increased fire frequenc and desertification. (Which will have consequences in turn... etc.)
Conclusion: The ecosystem is even slower than politics!
The United Nations Framework Convention on Climate Change states its objective as avoiding "dangerous anthropogenic interference with the climate system [...] threats of serious irreversible damage". The Earth is extremely stable. Even our massive manipulation of its ecosystem has been slowed down to a deceivingly illusive range of effects. And similarly, when we try to correct our mistakes, positive changes could very well be future events.
And just imagine the consequences of continued and indeed continued acceleration of carbon dioxide emissions... no thanks. No wonder the study was on when to hit the brakes.
Solomon, S., Plattner, G., Knutti, R., & Friedlingstein, P. (2009). Irreversible climate change due to carbon dioxide emissions Proceedings of the National Academy of Sciences, 106 (6), 1704-1709 DOI: 10.1073/pnas.0812721106
Comments
I have published this post for the researchblogging.org project. I can highly recommend this site for those who need light weight (and some crunchy stuff) takes on peer reviewed science (thus usually available to those with subscriptions only) and to those with some scientific training interested in blogging about science. It is my hope that integrating this project with TH!NK ABOUT IT will heighten the level of discourse here as well as advertise Research Blogging. Previous entries on my part have all been on my Ecowar blog (see my profile at Research Blogging).
Others have written about this paper as well. The above is just my summary (with a few reasonable additions). You might also want to read the following articles:
* RealClimate.org / Irreversible Does Not Mean Unstoppable
“the climate changes so far, both observed and committed to, are minor compared with the business-as-usual forecast for the end of the century. It’s further emissions we need to worry about. Climate change is like a ratchet, which we wind up by releasing CO2. Once we turn the crank, there’s no easy turning back to the natural climate. But we can still decide to stop turning the crank, and the sooner the better.”
* Global Warming Is Irreversible, Study Says
“But despite this grim prognosis, Solomon says this is not time to declare the problem hopeless and give up.
‘I guess if it’s irreversible, to me it seems all the more reason you might want to do something about it,’ she says. ‘Because committing to something that you can’t back out of seems to me like a step that you’d want to take even more carefully than something you thought you could reverse.’”
* ...or the original paper
Sea level rise - a certain change?
The warming ended ten years ago. Now we have cooling. This is the coldest year I remember (now snow in October!).
If this cooling lasts seveal decades, the ocean levels will GO DOWN. Because the water masses decrease their volume if cooled down.
Also… how many decades do the temperatures need to stand or go down, until you admit, that the rising CO2 emissions do not affect temperatures significantly? Ten years, thirty years, thousand years?
Vitezslav Kremlik,
Let us stop pretending we’re arguing here. You are arguing with science. It doesn’t matter if I “admit” anything about CO2 or not. And I believe you have already been guided towards the Real Climate article A warming pause?
, right!?
Sorry, Benno, but it is you who is standing against science. In 2007 the president of the World Federation of Scientists signed an open letter of 100 scientist to Ban-Ki-Moon, the UNO general secretary. He protested against the unscientific climatic hysteria.
Very well, but let us discuss the article. If the oceans shrink? Interesting. Should and probably will be investigated.
Oceans STOPPED rising 3 years ago. CO2 rises in the atmosphere are SLOWING in the past 3 years. Both sea levels and CO2 in the atmosphere may actually go DOWN in the coming years as the cooling continues.
Antarctica is COOLING and ACCUMULATING ice.
Mike, you are wrong, read the article linked to in my comment above.
Another Research Blogging blogger has covered recent research in another important greenhouse gas, methane: Blog Action Day: the Methane Pulse.
Yeah, I should have said “if” cooling continues. That way I get the same message accross without ever being wrong. After all, I said “IF”.
Also, tried reading that link you just posted, it isn’t working for me.
I’m sure copyright stops me from putting the graphs of the paper directly into my article here. But if you want to look at them, here’s a deep link for you.
Sorry, but I can not really see any “climate hysteria”. If anything can be called a consensus I think it is the IPCC’s position, and the measures probosed are very modest, compared to the consequenses “we” might find.
But since “we” will intially be poor people living South of sahara, i tha pacific etc. the problems fail to cause anything near to hysteria. Do you remember the picture the guy from Der Spiegel showed in Copenhagen, with Kölner dome under water? Such pictures hysteria, because it was a picture of Europe. When it happens in the third world we don’t seem to care.
Moreover, it seems the US National Oceanic and Atmospheric Administration seem to agree with Benno, Solomon et alt. Sea levels are rising.
Cooled water contracts. It takes years to cool down the huge oceans. Just as it takes time to freeze something in a fridge. So sea level (volume) is a lagging indicator. It lags behind SST (sea surface temperature).
SST is flat in the last 10 years. Soon the ocean level will go down too. It takes some time.
SST and sea level graphs here:
http://wattsupwiththat.com/2009/07/22/9507/
Interesting graphs, Vitezslav. And interesting source… “wattsupwiththat.com” is the blog of retired weatherman, Heartland Institute related Anthony Watts. Consider it.
* The video that Anthony Watts does not want you to see: The Climate Denial “Crock of the Week”
* Source Watch / Anthony Watts
You forget the human persons: peace or war?
Which war?
Overpopulation ..
we must give a well brought up education to all women of the world. It is necessary to begin with it and the development of new energies
Paul, are you saying war is enevitable? I hope not! But war is also something I have been blogging about
I hope it is evitable ... but overpopulation is not good!
Cooled water contracts. It takes years to cool down the huge oceans. Just as it takes time to freeze something in a fridge. So sea level (volume) is a lagging indicator. It lags behind SST (sea surface temperature).
SST is flat in the last 10 years. Soon the ocean level will go down too. It takes some time.