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Global Dimming
wiredog writes "The Guardian reports on research which shows that the amount of sunlight reaching the Earth's surface has decreased by 10% in 30 years. This has implications for global warming models and, especially, agricultural output."
Quite weird - there was an elderly farmer saying much the same thing this morning on my bus to work.
I'm pretty sure he wasn't a guardian reader, it's just something he'd noticed over the years.
At the time, I thought he was talking crazy talk...
I suspect that some of this global dimming is due to pollution from sulfates (coal), jet contrails, and dust from wind-borne erosion. Sulfate and particulate pollution provides nice nucleation sites for cloud formation. These pollution-created artificial clouds probably reduce global warming (the article mentions this effect and a correlated decrease in cloudiness and increase in temperatures in the 1990s).
The scary part comes if we reduce these forms of pollution, reduce cloudiness, and thus accelerate global warming. Whether we like it or not, humanity is changing the climate -- as attractive as it seems, preservation is impossible. At this point, it might be better to think about climate engineering -- deciding how we want to change the climate rather than holding on to the false hope that we can avoid changing the climate.
Two wrongs don't make a right, but three lefts do.
Every day, we get enough sunlight to power 27 years worth of the world's energy needs. Now, I thought about the implications of that. Obviously, we couldn't absorb/store the entire amount, but if we could put a dent in it, we'd have some global cooling. That is what this article is about.
On a similar note, the US could obtain all energy from the sun if it were to install a 200 mile square solar installation (assuming 15 percent efficiency... easily doable today). I say, put a dime of tax on each gallon of gas and use this money to subsidize solar generation - one of the only energy producers out there with net positive energy (more energy produced in the cell's lifetime than it takes to produce the cell itself). Hydro, wind and solar... I can't wait for the day.
On yet another related note, I'm in the process of building a solar/NiMH PC. I'm simply going to use store-bought NiMH rechargables to store excess daytime solar input. It certainly won't be cost effective but it'll be pretty high on the geek factor.
Life is the leading cause of death in America.
Also, it seems that the assumption has been made that the sun produces constant output. I don't think we can make this assumption. The sun, as a system, is way bigger than our atmosphere. Until we have thousands of years worth of data, observed from outside the atmosphere, we can't prove that solar radiation is a constant. In fact, since solar flares temporarily increase solar output, you could postulate that thousand year trends in flare frequency and magnitude could affect the overall output of the sun.
So, while global dimming may or may not affect us in the short term (on the scale of centuries) and pollution is still bad (again very long term effects are unrecorded, but it's obviously very bad in the short term (again measured in centuries) and it is ugly), I'm still not all that concerned that the world is going to ice over or boil away any time soon.
i don't like my old sig.
Good: We'll all have great skin for starts.
Actually, the article mentioned that it was visable and infrared light that was being blocked by an excess of clouds, not ultraviolet. Add to this the fact that our magnetic feild is becoming less polarized, in the process of flipping. As it does so there will be a bunch of little poles (places where the magnetic feild points into the earth not parrallel to it), guiding in additional radiation (and aroras, yay!). So if anything we will have more problems with bad skin not less.
Also, as the earth has warmed we have seen an the wet places getting more precipitation and the dry places getting less. And the article said the dimming was not constant, just that we have had more clouds and the clouds obviously block light, but the deserts, with no precipitation will have fewer clouds and thus less dimming.
My prediction: the world will be divided into radsuit wearing deserts desert dwellers, and mutant frog men, who live in swamps.
Although you probably meant this as a joke, it might be. The amount of light people recieve affects lots of physical things. Chronically light deprived people (such as those who work night shifts) are heavier on average than those who don't. Lack of sufficient light also affects alertness and mood, and not only in those who have seasonal affective disorder.
That being said, I don't think a 10% reduction in light would cause a significant increase in obesity, but it might be an interesting experiment.
I like my beverages with warning labels!