Climate extremes and the carbon cycle
Anthony Watts has copied and pasted a press release about a new paper in Nature, which discusses how extremes of weather can have an impact on the carbon cycle. He called it "Vicious carbon cycles". I saw this paper myself and thought it looked an interesting, if concerning, area of research. It's by Reichstein et al and called: Climate extremes and the carbon cycle, Nature 500, 287–295 (15 August 2013) doi:10.1038/nature12350.
This diagram illustrates how extreme weather can affect the carbon cycle (from the Nature paper). Click the image for a larger view:
What the paper is suggesting is that there is more evidence that indicates that climate extremes, like droughts and storms can cause terrestrial carbon to decline, which offsets to some extent the expected increase through plants' response to the higher atmospheric CO2. (C3 plants grow faster with higher CO2, all else being equal). The paper sets out a way to help improve the understanding of these interactions. There are a number of news articles about it if you want to read more.
The carbon cycle and the biosphere - up north in the boreal forests
I intended to keep this short, but the above paper reminded me of another recent paper, this time in Science. It's by Graven et al and is called Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960, Science DOI: 10.1126/science.1239207. So far it's just in ScienceExpress, but should show up in the main journal soon-ish.
What this one is exploring is the reason for the extra bounce in the seasonal CO2 levels as time goes by, in some parts of the northern hemisphere. In particular, they found that looking at CO2 levels at three to six kilometres up in the air in the region north of 45 degrees latitude, the seasonal amplitude of CO2 levels has shot up by 50% since the 1950s. This contrasts with the seasonal amplitude of CO2 at 10° to 45°N, which has expanded by less than 25%. They figure that it's got to do with changes in the boreal forests up north and signals a major shift in the carbon cycle.
They discount the effect of wildfire, oceans and fossil fuels. After discussing their reasons, the authors state:
We are led to conclude that ecological changes in boreal and temperate forests are driving additional increases in the summertime uptake of carbon. This inference from atmospheric data is qualitatively consistent with expanding evidence for significant changes occurring in these ecosystems. Forest inventories show increased stand area and biomass (27, 29). Other ground-based studies show that evergreen shrubs and trees are migrating northward in response to warming (43–45), and fire, logging and other disturbances (46, 47) are shifting the age composition toward younger, early successional forests that experience shorter, more intense periods of seasonal carbon uptake (25, 48). Satellite observations generally show trends toward increased greenness in northern ecosystems (4), although many areas of the boreal forest show browning trends in recent decades (49, 50). The atmospheric evidence helps to quantify the aggregate effect of these, and other, types of ecological changes over the past 50 years.
While the animation below is more about CO2 closer to the ground, you can see the difference between the northern and southern hemispheres in regard to seasonal fluctuations of CO2 (as featured on the NOAA website). Use the bar at the bottom to skip through if you don't have the full three and a half minutes to be mesmerised by the whole video.
The carbon cycle and the biosphere
What interests me in these two papers is the fact that they are getting more into the detail of changes that are happening to the world. Looking more specifically at changes in the biosphere and changes to the carbon cycle, not just the atmosphere and oceans, and considering how they affect the entire system. I think in the next few years there will be a lot studies like these ones being published.
The WUWT Illiterati Society
Anyway, here are some comments from WUWT in response to the top paper. The commenters have nothing but disdain for anyone who adds to the world's knowledge. You think this is an enlightened era? Well, it wouldn't be if the WUWT crowd had their way. I'm amazed they made the effort to learn how to read and write given they have so much contempt for learning.
Here's a sample - two out of only six comments so far. That's one in three commenters have declared their allegiance to the Illiterati Society:
August 15, 2013 at 10:17 pm A further example of the ever-increasing number of passengers on the global climate gravy train sucking the growing teat of “further research required” requests.
August 15, 2013 at 9:45 pm One day someone will write a paper that doesn’t say wtte “the demand for further research remains very high”
Now I've finished this there are more comments pouring in on WUWT. I haven't done a count to see if the one in three illiterati still holds true. However, I'll leave you with a comment without which no WUWT article would be complete - an ice age cometh!
August 15, 2013 at 11:26 pm Whatever. None of this will stop the coming ice age.