07 January 2009


Time for a converse to the usual question place note -- here's a place to contribute suggestions for the blog. Topics to cover, display methods, ... whatever would make for a more interesting and useful blog. I'll particularly address this to the science teachers, as I would like to be helping you and your students learn about science in general, and my science(s) in particular. But all constructive ideas are welcome.


Anonymous said...

What are the climate effects of the 'Asian Brown Cloud'?

Negative from albedo? Positive from Soot and GHGs? How does it balance out?

Robert Grumbine said...

Question rather than suggestion, and unfortunately, far enough from things I know that I can't help much.

The net effects are, last I saw (and this isn't an area I look at a lot) still being looked at. One part of the complexity is that you need to consider effects on what. Warming in one area, due to one of the effects, can cause cooling in another (the energy is absorbed released in area 1, so doesn't warm area 2). Ditto rainfall. The net could be zero, but if the distribution changes, that can be a climate change.

Anonymous said...

I'd like to see a topic on how the anthropogenically enhanced greenhouse effect warms the oceans.

I've read the RC take on this, but it's the only one I can find and another explanation might help me understand it better.

Disagreeing that AGW can warm the oceans does seem to be something that keeps reappearing in debates and I'm sure I just don't get the *detail* enough to counter such arguments.

Robert Grumbine said...

Anon: Could you point me to which description you read, and describe what you found insufficient or unclear about it?

In terms of debates ... well, debaters are there to argue a position they've already committed to and which evidence will not move them from. I describe more about this in Discussion versus debate.

Also, what level of detail are you looking for? The fundamental is straightforward -- more radiation from more greenhouse gases towards the surface (ocean or land) leading to more heating of that surface (conservation of energy). We can elaborate that up through the quantum mechanics of how the radiation moves around and interacts with matter and details of how the energy gets mixed into the ocean.

Anonymous said...

I was thinking about mountains and the force of the techtonics plates that push them to create moutains. Since the plates are moved by the earth's core's hot liquid, that means it won't stop moving. Is it possible to harness the power of these plates to create a renewable energy?

Anonymous said...

I added the techtonic plates power suggestion, so one more thing: since the hot liquids cause the plates to move they make mountians. So could it be possible that the sun contributes to heating this liquid to make the plates move? And if so, is that why planets far from the sun are realtivly flat, because they don't have hot liquids to push their plates?

Robert Grumbine said...

Interesting thoughts. To start with the second, no, the sun doesn't play a role in heating the earth's interior. The basic structure of the earth is a solid inner core, a liquid outer core, and then more or less solid rest of the earth. Throughout that structure, there are radioactive materials (uranium, thorium, and potassium are the main ones as I recall it). As the radioactive material decays, it heats up the surrounding rock or liquid. The liquid outer core is liquid because it's hot enough to melt the earth materials there. The inner core is solid because even though it is very hot, the pressure is so high that the liquid is forced to solidify. The pressure prevents the molecules from bouncing around freely enough to be liquid.

I'm not sure that the outer planets really are smoother than the earth. I know that Mars is actually much rougher than the Earth. Take a look at the Olympus Mons and the Valles Marineris. The Valles Marineris, at something like 4000 km long, completely dwarfs the Grand Canyon, for instance. The gas giants are pretty smooth, but gas pretty much has to be. The moons around the gas giants, say Jupiter's Callisto and Saturn's Iapetus, look pretty rough.

For generating energy, tectonics directly is hard to use. The principle is sound. Any time you have two things moving relative to each other, you can put an energy generating device between them and extract some of that energy as one plate moves away from your generator anchored to the other plate. The problem here is not the principle, but the fact that the plates move so slowly -- only 5 cm per year.

A method that _does_ get used is to tap the energy of the hot fluids driving the plate motion. That's the geothermal energy source. Iceland, I believe, is a leading user of geothermal energy. In part, this is because it sits on a 'hot spot'. Hawaii sits on another, as does Yosemite. I don't think either of them produces much geothermal energy, but the geology is right for it.