By Michael Haughey, June 16, 2009
The White House has just released the climate change impact report required by Congress every four years. This certainly is a breath of fresh air (so to speak) compared to the dark office corners where such information might previously have been relegated. It is 196 pages long and probably deserves a detailed read. If you are interested in reading it,
The report is released and discussed on this web site:
The report can be downloaded by chapter or in full at this web site: http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts/download-the-report
This report is apparently an update to the draft report released by the previous administration after a lawsuit to enforce the requirement by congress for the report.
Overall, I like what I’m seeing in the report given the intended audience. It collects a wide assortment of the available science and information into one document. It appears to be less constrained than the IPCC report, which needed a consensus from 130 nations for the summary document. A number of graphs are included and are generally quite easy to read and understand. The range of topics discussed is also broad, so it doesn’t appear that there are attempts to hide much, even if the emphasis in certain areas might be less than needed. After perusing the report, I do have some thoughts and comments:
There is a lot to discuss in the report. For starters, in the Executive Summary is included this sentence: “If emissions continue to rise at or near current rates, temperature increases are more likely to be near the upper end of the range.” I find that a little scary because the upper range of impacts should probably be a bit of a business-as-usual, or worst-case approach. If indeed that is the intent (and it may not be as explained in the release, that the scenarios are neither the highest or lowest possible), then it probably is not the upper range of possibility for one simple reason. That reason is that if we continue with business-as-usual, the rates of emissions release will increase. We have only to look at the impending methane crisis to see that. The release of methane from the Arctic is not really highlighted in the Summary (at least I didn’t find it), and that will be a powerful positive feedback mechanism. It is alluded to as “carbon” under the title “Carbon release and uptake” on page 16 of the summary. There is also this qualifier on page 26: “While analyses suggest that an abrupt release of methane is very unlikely to occur within 100 years, it is very likely that warming will accelerate the pace of chronic methane emissions from these sources, potentially increasing the rate of global temperature rise.” That is a bit like saying we don’t want to say it will happen, but don’t hold us to that. Maybe it will, or not.
The report summary mentions that methane is a shorter-lived gas in the atmosphere, or at least implies that. That leaves me wondering how much methane can be released and converted naturally to something else, and of course where does it go? Does that mean that eventually the carbon stored as methane can be released and converted into something relatively harmless? How long (in centuries or more I presume) would that take?
This statement is telling: “The European heat wave of 2003 is an example of the type of extreme heat event that is likely to become much more common. If greenhouse gas emissions continue to increase, by the 2040s more than half of European summers will be hotter than the summer of 2003, and by the end of this century, a summer as hot as that of 2003 will be considered unusually cool.” I would not look forward to a world like that.
Regarding possible sea level rise, on page 25 I found this comment “There is some evidence to suggest that it would be virtually impossible to have a rise of sea level higher than about 6.5 feet by the end of this century.” The referenced study is “Pfeffer, W.T., J.T. Harper, and S. O’Neel, 2008: Kinematic constraints on glacier contributions to 21st-century sea-level rise. Science, 321(5894), 1340-1343.”
This is not so reassuring when one realizes that Kinematic (or rather kinematics) means, from Dictionary.com:
” – noun (used with a singular verb) Physics. 1. the branch of mechanics that deals with pure motion, without reference to the masses or forces involved in it.
2. Also called applied kinematics. the theory of mechanical contrivance for converting one kind of motion into another.”
I have to wonder if there was an assumption that water could only travel from glaciers to the sea as ice (in other words, mechanically). Further I wonder if the study only covered glaciers as implied in the title, and not the huge ice sheets on Greenland and the Antarctic. The authors could have assumed that the ice sheets just can’t melt that fast and proceeded from there. What we would be seeing, then, is a bit of circular logic. Certainly if the ice on Greenland or on the Antarctic were to melt, the resulting water would find a path to the sea. The big question here would be what is the temperature at the land-ice interface two miles or so down where the ice sheets meet the land. Perhaps someone can find a copy of that article and review it?
This is somewhat acknowledged in the statement on page 26: “Rapid ice sheet collapse with related sea-level rise is another type of abrupt change that is not well understood or modeled and that poses a risk for the future.”
Hurricanes are also afforded some summary discussion in the report. This statement on page 36 would make a good highlight of that section: “Even without further coastal development, storm surge levels and hurricane damages are likely to increase because of increasing hurricane intensity coupled with sea-level rise, the latter being a virtually certain outcome of the warming global climate.”
There is a lot that is known about hurricanes, and even more that is not. Clearly global warming will create conditions for stronger hurricanes, and sea level rise will increase the potential for greater storm surge damage. I have noticed, however, that hurricanes are very fickle. They seem easily torn apart by what is known as wind sheer, or basically a cross wind that disrupts the circulation of the storm. I would expect global warming to also increase the winds that tear apart hurricanes. The question I have, then, is will there come a point where the hurricanes are torn apart faster than they get stronger? Even if that occurs, will there still be some monster storms that get through and make devastating landfall?
The Gulf coast is particularly vulnerable to sea level rise and the associated impacts of global warming. Consider this statement (regarding the Gulf coast) on page 63: “27 percent of the major roads, 9 percent of the rail lines, and 72 percent of the ports in the area shown on the map on the previous page are built on land at or below 4 feet in elevation, a level within the range of projections for relative sea-level rise in this region in this century.” Additional discussion of the amount of infrastructure and the value of commerce conducted in the region really highlights the potential severe disruptions. Considering how little of New Orleans has been rebuilt, one can only imagine the extent of this area that might eventually be abandoned due to climate change impacts.
My overall impression of this report is that it is a hopeful step in the right direction. It may seem gloomy, mostly because that is the reality. However we must keep in mind that the first step in solving any problem is to fully understand the problem. The more the problem is understood, the more the solution becomes self-evident.
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