Tropical rain outside the tropics - a visible result of climate change.

[marsden_online]

http://sciblogs.co.nz/hot-topic/2010/06/22/when-the-rain-comes…/

As the oceans warm up, more water vapour enters the atmosphere, and because it is itself a heat-trapping gas this adds to the warming. This positive feedback is important because it increases the amount of warming triggered by the CO2, but it’s also important because of impacts of the increase in water vapour itself. The increase has been measured: there’s about 4% more water vapour in the atmosphere now than there was 30 years ago, and I suspect that we’re now seeing the effects of that on our day to day weather.

Water vapour is sometimes described by meteorologists as the “fuel” that drives storms. As water evaporates from a warm ocean, it cools the surface and transfers energy into the atmosphere. As the water vapour condenses into clouds and rain, that energy is released, intensifying the storm. More water vapour, stronger storms, heavier rainfall.

4% extra water vapour doesn’t sound like a lot, does it? But it’s enough to change the probabilities of heavy rainfall events in two ways. Firstly, the frequency of heavy rainfall events will increase, and secondly the amount of rain that falls in the heaviest events will increase. Take a look at this graph (from NASA’s Earth Observatory feature on the costs of climate change):

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Also from Sciblogs this week:
- I know that everyone here is sufficiently educated to know that camels store fat, not water in their humps. This post looks at other ways they are adapted to a low-water environment -
http://sciblogs.co.nz/bioblog/2010/06/22/the-camels-hump/

- Birds have friends too - http://sciblogs.co.nz/skepticon/2010/06/23/ravens-and-empathy-the-role-of-bystanders-after-conflict/

What was found was that birds who were the recipients of high intensity conflict (eg hitting) were more likely to receive interactions with high value bystanders. In other words, when birds got into a serious fight their friends came over afterwards. The correlation with conflict intensity implies that the “friends” knew when the victim would be more distressed and would need to be calmed. This insight further implies some level of empathy.