Freeman Dyson Takes a swipe at climate change science

From Realclimate.org

In the New York Review of Books, Freeman Dyson reviews two recent ones about global warming, but his review is mostly shaped by his own rather selective vision. 1. Carbon emissions are not a problem because in a few years genetic engineers
will develop “carbon-eating trees” that will sequester carbon in soils.

There is a lot of criticism of Dyson's article here - a lot of it probably valid. But some people seem to be writing off everything Dyson says based upon his involvement with the pie-in-the-sky Orion Project.

There was nothing intrinsically wrong with the Orion concept. It might not be the best engine design we have (and would probably never be usable in our atmosphere) but it is a good idea.

We should take our own advice, and stick to talking about our areas of expertise - leave the nuclear physics to the nuclear physicists ;).

Generally, I imagine that the trees Dyson talks about are probably somewhere in our future - the question is whether the trees would come quick enough to stop problems if we just go on with business as usual.

There is no reason not to pursue ideas like this - all ideas should be pursued to some degree. The danger lies in reliance upon one solution alone.

Tropical tropospheric warming

Warming maximum in the tropical upper troposphere deduced from thermal winds - Robert J. Allen & Steven C. Sherwood - Nature Geoscience (subscription required)

The apparent lack of a tropical tropospheric warming signal in observations has been a problem with climate change predictions for some time. However, the direct temperature record has many problems - there have been many changes in the observation mechanisms:

non-climatic artifacts due to station relocations, observation time changes and radiosonde type or design changes...

leading to difficulties in interpretation. Earlier studies have attempted to correct for these artifacts with uncertain amounts of success. Instead, Allen and Sherwood use the thermal wind balance relationship to back calculate spatial temperature gradients from the significantly more trustworthy wind fields.

The "thermal wind" is a vertical shearing of the geostrophic wind arising from the pressure variations caused by horizontal temperature variations. The geostrophic wind is the wind that balances the Coriolis force with the pressure gradients. (See Wikipedia for thermal wind
and geostrophic wind). These relationships are weak near the equator, where the Coriolis force vanishes, but they appear to hold for winds averaged over long timescales.

This data gives a time series of spatial gradients in temperature, which can be integrated from a (collection of) "trustworthy" point(s) to give the temperature structure of the atmosphere. Allen and Sherwood cautiously report a warming trend in the upper tropical troposphere that is consistent with models showing climate change.

Did You Publish Today?

This column, I'm sure you realize, dear fellow academics, is not for you. You don't need me to tell you that when you're working it can sometimes look to the rest of the world like you're curled up in front of the fire petting the cat. This column is for your husbands, wives, partners, parents, siblings, friends, and strangers who ask questions like "When are you going to graduate? It's been five years already." Or "Why hasn't that book come out yet? You've been working on it forever!"

Chronicle of Higher Education

Global warming reduces hurricanes?

Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions - Knutson et. al; Nature Geoscience - subscription required :(

Changes in large-scale climate projected by IPCC used to force regional Atlantic Basin Model to assess hurricane frequency changes that might be driven by climate change.

A high-resolution simulation of the present-day Atlantic basin is nudged on large spatial scales to match the reanalysis data (numerical realizations of the global atmosphere that assimilate the many observations that exist into the models).
Hurricanes simulated by the model are not as intense as observed - probably a result of insufficient resolution. Storm tracks in the model are realistic.

The warm-climate runs show a general reduction in storm frequency. Will Global Warming reduce the hurricanes we have to deal with?

I am not so sure - I see a problem with their methodology: the "warm climate" simulations are a simple rerun of the present day simulations with the day to day and year to year variations unchanged, with just the mean temperature (and probably moisture) profiles increased as predicted by the climate projection models.

They thus make the implicit assumption that the climate variability will be unchanged under global warming, an assumption that seems unlikely and is generally not found to be true in climate projections.

Unfortunately, future variability is a hard thing to account for - the current models are not sufficiently accurate that I would trust any specific details of variability.

Another observation is that near storm rainfall is increased - rainfall comes from condensation, which releases latent heat - a source of energy for the hurricanes - so the hurricanes should perhaps be stronger on average. Even with a reduced frequency, if the number of extreme hurricanes increases, then we are probably worse off, both financially and environmentally - the global ecosystems will have evolved "assuming" a certain distribution of hurricane intensities in an average year - changes to this distribution could change many things: mixing of nutrients and/or silt throughout the oceans, rainfall amounts in rivers and lakes in regions near the eastern coasts of the continents that tend to be fed by the precipitation from the storm systems that form out the decaying Hurricanes.

These are complicated questions that I don't know enough to answer.

I suspect that if this experiment was rerun with an increased warm climate variability, the results might be quite different.

Second PhD Comic post in about 12 hours

I get exactly where Tajel is coming from in this one - I have the same issue with my Family name - the 'e' near the end throws most people.

And it doesn't help that my Australian accent apparently makes 'e' sound like every other vowel (and some consonants) when I spell it out... The accent also makes 'Joe' sound like John or Jason or James to a lot of Americans (apparently)

SMS data rate is 4x more expensive than data from the Hubble

You know how the mobile carriers charge you a couple cents to SMS a few characters' worth of text over their network? When you add it up, you're paying about a zillion bucks a meg for that traffic -- seriously! A space scientist from Leicester has calculated that SMS data is four times more expensive than receiving data from the Hubble space telescope.

boing boing

Climate makes profound mark on ecosystems

SYDNEY: The largest study of its kind reveals that global warming is already having a massive effect on life across the planet – greater even than habitat loss and deforestation.

The study, which analysed nearly 30,000 data sets stretching back to 1970, suggests that warnings spelt out last year by the U.N. underestimated the impact of the problem.

Significant changes

The data set covered phenomena as varied as the earlier leafing of trees and plants; the movement of species to higher latitudes and altitudes in the northern hemisphere in response to warmer weather; the shrinkage of glaciers and melting of permafrost; and changes of bird migrations in Europe, North America and Australia.

The study concludes that "significant changes" are already occurring among natural systems on all continents, with the exception of Antarctica, and in most oceans.

Published today in the U.K. journal Nature, it goes beyond the scope of the landmark report issued by the U.N.'s Intergovernmental Panel on Climate Change (IPCC) in February 2007.

From Cosmos