Dr. Roger Pielke Sr. sends word of this new paper now in early release at the Journal of Climate. The paper suggests humans have strong impacts on the local climate, but not always through the pathways commonly touted as being the culprits.
Greenhouse gas policy influences climate via direct effects of land-use change
Abstract
Proposed climate mitigation measures do not account for direct biophysical climate impacts of land-use change (LUC), nor do the stabilization targets modeled for the 5th Climate Model Intercomparison Project (CMIP5) Representative Concentration Pathways (RCPs). To examine the significance of such effects on global and regional patterns of climate change, a baseline and alternative scenario of future anthropogenic activity are simulated within the Integrated Earth System Model, which couples the Global Change Assessment Model, Global Land-use Model, and Community Earth System Model.
The alternative scenario has high biofuel utilization and approximately 50% less global forest cover compared to the baseline, standard RCP4.5 scenario. Both scenarios stabilize radiative forcing from atmospheric constituents at 4.5 W/m2 by 2100. Thus, differences between their climate predictions quantify the biophysical effects of LUC. Offline radiative transfer and land model simulations are also utilized to identify forcing and feedback mechanisms driving the coupled response.
Boreal deforestation is found to strongly influence climate due to increased albedo coupled with a regional-scale water vapor feedback. Globally, the alternative scenario yields a 21st century warming trend that is 0.5 °C cooler than baseline, driven by a 1 W/m2 mean decrease in radiative forcing that is distributed unevenly around the globe. Some regions are cooler in the alternative scenario than in 2005.
These results demonstrate that neither climate change nor actual radiative forcing are uniquely related to atmospheric forcing targets such as those found in the RCP’ s, but rather depend on particulars of the socioeconomic pathways followed to meet each target.
Louise says:
December 8, 2012 at 11:54 am
“So models are good science now?”
In my opinion this is not science at all but attempts by wannabe central planners from Berkeley, California, to find the optimal 100 year plan for their desired centrally planned global economy.
I’m very sure this will come to absolutely nothing (maybe devastate one or two continents in the process though, given somebody is foolish enough to give these kids any influence).
Let me get this straight…
they took a model which fails at 72 hours 100% of the time, Then they plug into it another model to create one of the variants in the first model, which affects three other ares of the first model and its feed backs…
does any one else get the feeling that we are spinning in circles here? And given the law of averages, the failure rate declines to 100% at 3 hours
The take-home message here is that when you set a goal in terms of radiative forcing, e.g. 4.5 w/m2, the results you get don’t just depend on the goal; they also depend on the path you take to reach that goal. That seems pretty obvious, but it’s not a bad idea for someone to take a stab at figuring it out what difference it could make. Usually, in things like this, the first effort may end up being less than accurate, but the first effort is what leads to later efforts.
If you cut down the boreal forest, you’ll probably reveal snow for part of the year, if it still snows at a given location in the year 2100. For much of the boreal forest, it probably will snow; even if 3 meters of snow cover are replaced by 10 cm, the top few mm will reflect just as much as it did before. Not that the change would necessarily be that radical, but even even if it were–no difference while the snow is there.
Pine trees and the like are pretty dark, so if they were all cut down, albedo would probably rise, no matter what was revealed; snow, grass, rocks…maybe soil wouldn’t reflect so much. But even fallen pine needles might be brighter than the live ones on the trees.
What do they assume would replace the forest? Would they grow biofuels where the boreal forest was, as the abstract seems to imply? And what do the authors assume would be grown? Hardy Northern wheat? Algae? Cyanobacteria? Genetically engineered fast-growing lichen, or something weirder? We don’t know, because the article is paywalled. So, we’re stuck with just the abstract.
Here’s a thing about paywalls, though: If you work at a major university, you can often get these articles online, because the university would have online subscriptions to many journals. You could read the article, print it, even download a PDF from any computer within the University. If you don’t work at a university, many of them still open their libraries to the general public, so you can go in and read, print, or email the article to yourself. Bit of a chore, but it can be done if you want to badly enough–it’s more efficient to wait until you have a few you want, like half a dozen. Of course, though, this only works with journals that the university actually subscribes to, and that’s not always the ones you want. My local Uni doesn’t get GRL; I don’t know whether they get J. Climate (where the above article appears).
It would be tempting to download a pdf of an article and stick it on a server somewhere, so everyone could see it, but that’s not something to jump into without thinking it through. For copyright law (US), copying an article for scholarly purposes is allowed, and for people to read it and discuss it is “scholarly purposes.” But making the article available to the world would give the journal a legitimate (in court) complaint, to say you were cutting into their profits.
In other words, old school “ecology” – you know, the type that was the comfort zone of conservationists 50 years ago – is the tried and true way to avoid problems. All this new Age stuff is a waste of time.
Boreal deforestation.. Just what the ex-greenies like GreenPeace and WWF ordered.
They would do it too, without a blink, if it helped their cause.
ps.. they now have one model that says it should be done.. that’s all that is needed.
Now:
Deborealize to decarbonize to deindustrialize.
What could go wrong?