30 December 2009

Happy many things

Didn't mean to disappear for so long, and, unfortunately, it'll be a while yet before I'm posting again.

First, though, happy Winter Solstice, New Year, and Perihelion (January 3rd).  Hope that all is going well, and you all have a good new year.

I managed to mistake cleaning up a tangle of wires, and disconnect the internet from home.  So it'll be a while yet before I post regularly.  But, once that's taken care of, first up will be a look at the claim of 'but temperature leads CO2 during the ice ages'.  Somehow that's taken to mean that the current CO2 levels are explained by earlier warm periods (they're not) or that CO2 cannot affect temperatures (it can).  The post will have the full illustration.


03 December 2009

Technological progress

A couple of videos that caught my eyes. First is one on an upside of technological progress -- cars today are enormously safer in a crash than cars 50 years ago. This video shows the collision, and the driver crash test dummies, between a 1959 and 2009 car. The 2009 car undoubtedly weighed far less than the 1959. Superior engineering is the key -- a point that Consumer Reports routinely winds up making in their vehicle reviews.
Crash test video.

Digressing a second: It occurs to me that Consumer Reports is probably the popularly available magazine that does the most consistent job of displaying a scientific approach. The typical review article shows what they were testing, how they tested it, adds information about how significant the test differences are like, and so on.

The second video is one on a topic that weather and climate folks are probably more than a little tired of. Namely, the accusation that we didn't realize that there's such a thing as an urban heat island effect. I've never taken up the search seriously, but a few years ago, an urban heat island reference was in the Bulletin of the American Meteorological Society's '50 years ago' column. So, well-known (the referenced article was clearly not the discovery of the effect, just another illustration) by the early 1950s.

The video is from Peter Sinclair's Climate Crock of the week. In it, he carries out a good practice for science -- suppose an argument is correct, then look for observations that will confirm or reject that argument. The argument is that the urban heat island is producing the observed warming trend. Ok, says Peter, if that's the case, we should see that the trend is the strongest (most positive) in urban areas. Now, it isn't hard to figure out where the urban areas are. Nor is it hard to map out what the trends are for different areas of the globe. Compare the two.

In truth, as he illustrates, the warmings are highest in areas that have very few people -- Siberia, the Arctic, and Hudson Bay being leading zones. His figure is for the 2008 anomalies -- after the 'decade of cooling' (what cooling?), rather than the 30 year trends ending that date. If anything, the trend map is worse for the urban heat island fans, as it shows large trends across northern Canada as well.

Nothing obvious connecting the two videos. But the thing is, I have a lot of confidence in engineers to solve engineering problems. One such problem is car safety. Others would be things like more efficient cars, new and better ways of producing energy, and so on. In the 1950s and 60s, it was an article of faith in the car industry that customers did not care about safety. And that if they were forced to engineer safety, they'd go out of business (it would be too expensive). Instead, we have vastly safer cars today, and tens of thousands of people are still alive because of it. The engineers were more than up to the challenge. On the other hand, if the engineers aren't allowed to work on a solution, they won't find it.

I'm not taking up geoengineering in this; that's a topic for a lengthier post of its own. I'm just minded that there are quite a few climate-related technology issues that exist regarding efficiency of old technologies, or new technologies to develop, that we're being told would drive companies out of business, cost jobs, and other alarmist statements -- as there were in the 50s and 60s regarding automobile safety. Yet the engineers found ways of improving safety even as we drove more, drove lighter cars, and so on. And the companies didn't go out of business, indeed make quite a lot of money.

02 December 2009

Fake ice

The ice is real ice, but the satellites are being fooled.  Actually, not even that.  The satellites are correctly reporting what they're seeing, but the humans have been making an assumption that no longer holds true due to change in the Arctic.  A friend pointed to an interview (audio only) of David Barber, on Quirks and Quarks on CBC.  Early on, he mentioned how the satellites were being fooled.  That isn't exactly what's up, but was the right answer for the circumstance.  I'll take a bit more time to discuss the details of what is happening on this part of the story. 

Our standard method for observing sea ice from space is to use satellites to measure the microwave energy emitted from the earth's surface.  Sea water is a very bad emitter, so has a very low brightness temperature.  Sea ice is a pretty good emitter, so has a much warmer brightness temperature.  You go through a couple of elaborations on this, and out pops the fraction of the surface that is sea ice instead of sea water.

You can also be a little more demanding than that.  Particularly in the Arctic, this makes sense.  The elaboration comes from the fact that not all ice emits microwaves equally well.  Salty ice is a better emitter than fresher ice.  In the summer time, when ice floes do some melting (but not enough to get rid of the whole floe for the ones we're interested in), it is the saltier parts of the floe that melt away first.  This is the same thing happening when you salt the sidewalk -- the salt lowers the melting point, and the salty parts melt first.  When you get to this time of year, and the melting stops, what is left is a relatively fresh ice floe.  It is also called 'multiyear' ice, since it's now in its second winter.  With a more detailed analysis of the microwaves, you can try to distinguish between the first year ice (saltier and a better emitter) from the multiyear ice (less salty, but still a better emitter than sea water) from the sea water (very poor emitter).

Analogy for the remote sensing: The satellite is listening to the surface.  Sea ice is much louder than sea water, so you can start by just checking how loud things are.  Louder = more sea ice.  You can then listen a little more carefully.  Multiyear ice is a little quieter than first year ice, and a little different pitch.  So there's a choir of sea ice, and the multiyear ice is, say, the sopranos singing a little quiter than the basses (first year ice), but both are much louder than the baritones (sea water).  If you've listened to a choir, a band, or just a room of people talking (and deciding how many people were in it, and how many of them were men vs. women), you've done the same sort of discrimination that we're doing with the satellite observations.

Now for the spot where we were fooled.