Sunday, October 09, 2011

Climate change: what is at stake?

The more I talk with people about their attitudes towards and feelings about climate change, the more I have discovered that many (perhaps most) well-educated and socially-engaged people have only a somewhat vague idea of the nature, scale and likely timing of the various kinds of dangers we face on our current path. And so, when I came across this summary from Joe Romm, I immediately thought that many of my readers might find it a useful resource to peruse, bookmark, reflect upon and share with others. If you are not really sure what impacts mainstream scientific research currently considers likely from a middle of the road business as usual scenario (i.e. not worst case), then this post lays out many of the key issues in an accessible way.

The figure included above is from MIT research from 2009 and shows the likelihood of different temperature outcomes based on two broad scenarios. On the left is business as usual. This is not the worst case and does not include slow feedbacks. On the right is a world where we take aggressive global action to reduce carbon emissions. The temperatures are the average global difference between the world in 1990 and in 2100. Since most other discussions used pre-industrial temperatures as a baseline and the world had already warmed by about 0.5ºC by 1990, then this needs to be added to the numbers to compare with other publications. My main criticism of the image is in the choice of colour. A rise of 3.5-4.5ºC above pre-industrial temperatures can in no sense be understood as reassuringly green. Such a change in the space of a century would be unlikely to be compatible with industrial civilisation as we know it or the possibility of feeding anything like the 9-10 billion people projected to be around by then.

5 comments:

Sarah said...

(This is Bradley, from Bradford Littlejohn's blog) Byron, I thought you should know: after reviewing some of the data more carefully, I've recently had to admit to myself that, yes, global warming is probably anthropogenic. Thank you for your persistent links and dedication in this area. It helped me partially in coming to this conclusion.

Now I'm in an awkward position, given my job. I'm not quite sure what I'm going to do...

In the meantime, I'm still not sure if the *effects* of global warming will be that bad. I'm especially unconvinced by the diminished-agricultural-yields argument. But on the other hand, the loss-of-wildlife-and-widespread-extinctions argument seems pretty solid. I'm still not sure at all about ocean acidification; I'm waiting on the results from a study I have in mind. But at least now I'm pretty sure global warming is caused by anthropogenic carbon emissions.

Regarding Evolution vs. Creation, however: I still can't find any good evidence for Evolution. :-)

byron smith said...

Hi Bradley, good to hear from you. Can you say a little more about what data were important in shifting your judgement on this? I appreciate your honesty in being willing to admit to a change of mind.

What is your job?

Why are you unconvinced about diminished agricultural yields? The impacts of climate change on food production are not limited to heat stress on crops (which may suppress global yields of major grains by 5-15% per degree of warming, according to some studies), but also include disruptions to the hydrological cycle, inundation (or salination) by rising sea levels, loss of glacial melt water, increased erosion and shifting distribution of pests and invasive species.

What is your study on ocean acidification and when you say that you are not sure, do you mean you are not sure it is happening, not sure that it is linked to anthropogenic CO2 emissions or not sure that it will have significant negative consequences?

Sarah said...

For a while I had been clinging to the possibility of negative feedbacks. Perhaps something (like cloud cover?) would kick in and stop the warming amplification? But the more I researched it, the more I saw the improbability of that idea. I don't think we can rule out negative feedbacks as absolutely impossible, but they do seem very unlikely; and in any case, we have no tangible reason to put our faith in them. That was the final step for me.

I work for a medium sized oil company based in Oklahoma. The company is privately owned by Reformed Christians and managed on 100% debt free principles, which is nice, so at least I've always felt good about avoiding the corruptions of Wall Street and the banks. My job is selling oil royalties in the London area. I sell shares in oil wells to small investors. They get a 20-25% annual rate of return, and our company gets expansion capital to drill more wells (sorry if that sounds like a sales pitch; it's not, I'm just describing my job). Naturally, coming to the conclusion that carbon emissions probably cause global warming is a bit unsettling to me. It is literally my job to help finance new oil wells. Hmmm. :-/

To clarify, I am fully convinced that agricultural yields will diminish significantly IF we continue along our path of industrial agriculture. But if we cease the madness and instead begin farming holistically, then I'm confident that we can actually *improve* our yields, even in the face of more droughts, pests, and invasive species. When I say “farming holistically”, I'm not just appealing to some fuzzy idea about working with nature; I have specific practices in mind. We need to plant perennial grains with deep roots to withstand droughts. We need to stop tilling the soil, so we can end erosion and establish a stable ground cover. We need to end the ridiculous practice of monocropping and take advantage of diverse canopies of crops, and creating ecosystems for all sorts of insects and their predators, not just one crop that only pests are interested in. I could go on for days. I don't have all the answers (nobody does), but I know there are already answers out there. I have seen farmers increase their yields in the middle of droughts. Reverse desertification. Eradicate thistles and thorns permanently without any herbicide whatsoever. Get rid of pests simply by increasing their brix rating. (I can talk to you more about all this if you want, but I have to tell you up front, I do prefer talking. It's much faster than writing comments and emails)

I suppose there's not much that can be done about rising ocean levels, though, or the loss of glacial melts. That land will pretty much be lost. But at least we'll gain a tiny bit more land in places like Greenland. :-)

Sarah said...

Most of all, we need to sequester more carbon into the soil. If humanity takes a concentrated effort towards doing this, then we can return atmospheric CO2 to pre-industrial levels in just a few years. It wouldn't be the end of climate change, of course, but it's probably the best thing we can do.

In my opinion, it seems the worst effect of global warming will be on wild species and ecosystems (extinctions, etc). Mankind can take care of himself in these unstable times, most importantly by changing his farming. But the sparrows, who neither sow nor reap, will suffer greatly. This truly concerns me.

Ocean acidification is clearly happening, and anthropogenic carbon emissions are clearly responsible. But I'm just not sure if the consequences will be bad. Thus far, I've only seen conflicting data. Some say the extra acid will hinder the formation of calcium carbonate in marine organisms. But others point out, “Hey, this isn't just 'extra acid' we're talking about. It's carbonic acid, which actually makes it easier to form calcium carbonate in seawater conditions.” (see here for a more in depth explanation of this argument.) Some real-live studies have shown decreased calcification, and some have shown increased calcification. The study I'm waiting on is this one. If that study doesn't provide a conclusive answer, I don't know what will.

Of course, there're plenty of reasons to oppose global warming. Ocean acidification is just one more drop in the bucket.

byron smith said...

Hi Bradley,

Many many apologies for not getting back to you sooner. I have been ill, away, hosting guests and very distracted for the last month or so and have spent little time online. I confess I initially missed these comments amongst all the emails I had to deal with on my return.

Thank you for your honesty and for being willing to share some of your experience. It makes my tardiness all the worse that your comments bore more than an average amount of significance.

You're right about negative feedbacks. As yet unknowns that render the issue far more benign are of course quite possible, but on the balance of evidence, relying on the existence of unknown effects to prevent disaster is not a particularly wise course of action.

I didn't realise that you're in the fossil fuel industry, which, as you say, makes these matters even closer to home for you. The financial model for your company sounds quite interesting (Bradford has told me a little more about it a day or two ago), though as you can probably appreciate, I am not a big fan of the fossil fuel industry as a whole. I'm particularly concerned about the practices of many the larger players, but the very concept of digging up inactive carbon from long term safe storage and putting it into the active carbon cycle is problematic even where it is done as ethically as possible in all other regards. Of course, in the end the decision of what to do is for you to discern with the aid your brothers and sisters in community. I will pray for wisdom.

I am also a big fan of more holistic farming practices that are less reliant upon nitrogen-based fertilisers, monocropping, toxic persistent pesticides and the mining of the soil through over-cultivation. I'm far less of an expert in this area and so base my pessimism on what I've read thus far about the scale of the task required to effect the kind of shift you're talking about (particularly in the face of the entrenched financial interests of certain agro-business multinationals). Perhaps social tipping points will be reached beyond which the momentum for such changes will be rapid. But there are certain features of the climate issue that seem to make that less likely. Happy to talk about that further.

As for ocean acidification, the synthesis reports I've read all treat it as a very serious issue. I've spoken with a number of marine biologists personally, who rate this issue as being as significant (or more) than overfishing. I note that the blog post you link to says that the Royal Society publishes "outright lies" and says that their report ought to be "consign[ed] ... to the waste bin". This doesn't give me great confidence in the academic credentials of the author, who would presumably publish their thoughts in a reputable journal if they really thought they had a good case against the RS publication.

The 2008 Wood, Spicer, and Widdicombe paper they cite at most length refers only to some species benefitting from acidification, which has been widely acknowledged in the published literature. I appreciate the fact that the picture is complex, changing and does not yet have high levels of certainty for all elements, but I get a strong impression that many marine biologists are very, very concerned about this.

That said, I agree that ocean acidification is but one aspect of the carbon problem and even if it turned out to be benign, there is plenty to be concerned with elsewhere to make leaving most of the remaining carbon underground an ethical imperative.

Thanks for your thoughts on this.

Grace & peace,
Byron