They also have an article on the hurricane stuff (which I've read) about the Webster paper in Science (which I've just skimmed). But the abstract is:
We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific Oceans, and the smallest percentage increase occurred in the North Atlantic Ocean. These increases have taken place while the number of cyclones and cyclone days has decreased in all basins except the North Atlantic during the past decade.
...hurricanes in the strongest categories (4 - 5) have almost doubled
number (50 per pentad in the 1970s to near 90 per pentad during the past decade) and in proportion (from around 20% to around 35% during the same period)...
We conclude that global data indicate a 30- year trend toward more frequent and intense hurricanes... This trend is not inconsistent with recent climate model simulations that a doubling of CO2 may increase the frequency of the most intense cyclones, although attribution of the 30-year trends to global warming would require a longer global data record and, especially, a deeper understanding of the role of hurricanes in the general circulation of the atmosphere and ocean, even in the present climate state.
Well, interesting stuff, somewhat complementary to Emanuel. A thing that struck me, and isn't mentioned in the Econ or Science (as far as I could see) is that "hurricanes only form when SSTs are over 26 oC", and the region with the most obvious increase is the N Atl, which has the lowest SSTs, and so might be "unsaturated" and more liable to increase (whatever that might mean).
4 comments:
Great minds move in similar veins (when it's the other way around it's time to watch out). This from Emanuel's AAAS interview posted on the latter's site:
"Besides the overall global trend of increasing hurricane intensity, the key issue of concern raised by our study is that the hurricane intensities in the North Atlantic for the last decade have been lower than elsewhere on the globe. It is likely that the differences among the different ocean basins is associated with natural variability. This implies that at some point within the next decade, there is the risk that the intensity of North Atlantic hurricanes could increase rapidly to the global average (with possibly a concurrent decrease in another ocean basin). The variation of Atlantic hurricanes relative to hurricanes in other basins in the context of known cycles of natural variability needs further investigation."
William, I don't have a subscription so can't see the Economist article. Do they estimate a capacity factor for offshore wind? (<40% or so might answer your question)
The economist thing was very broad-brush. They didn't tell me whether the cost-per-kWh for wind was max theoretical or has capacity factored in. Since the econ is nver v keen on wind power I'm assuming the latter, since it makes wind more expensive, but I don't know.
William, I searched around for offshore wind costs and I'm thinking it's likely that the prices quoted are only per installed watt. Operational lifetime would also seem a factor in comparing nuclear vs. offshore wind. There shouldn't be any reason why a well designed nuclear plant can't be in operation for ~60 years, it's difficult to find much information about offshore wind plant lifetime estimates, but it seems some are only for about ~20 years. (those seem to be for minimum estimated lifetimes though) Personally I think offshore wind might have great potential utility, but it'd be nice to be able to have a look at the real numbers. (any links would be appreciated, of course :)
If the numbers add up favorably, it'd probably be a good idea to build more offshore wind sooner rather than later, considering the rising cost of steel.
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