The BBC is a fabulous resource for anyone who likes things that range outside of the Americas. In the field of science I consider it one of the best general resources for the novice. In this particular article I perused most of the information from which you will likely garner "We don't know" and "It might happen" in regards to the link between the wild climatic changes we've seen in recent months and the ever present threat of global warming. What you might miss is at the bottom of the page. "Water on the ground cools the atmosphere around it a lot, and once this has dried out, the temperatures just accelerate. So there is some concern that these hot days may become more frequent over the next decade, but that is still uncertain."
Dr Haylock, who works for re-insurer PartnerRe in Zurich, Switzerland, and is formerly of the University of East Anglia's Climatic Research Unit, UK was quoted as saying.
Now this is very interesting. Take a look outside right now and you may see some of the warmest temperatures in recent memory across the country. While July is certainly the cause for much of the heat, drought and water use can be causing some of the change. What strikes me as the most important part of the idea is the death spiral it implies. As long as temperatures keep increasing, evaporation will increase, thus decreasing the available water supply, increasing local temperatures more. Think of it this way. When a puddle forms in your driveway does it evaporate faster when it's deep or shallow? Even if the surface area is the same, the amount of water that has to be heated is much smaller. This is because convection is a much poorer transport of heat than conduction thus the deeper puddle must be entirely heated to cause surface evaporation. There's a second side to this problem. Since all this water has evaporated due to higher temperatures there is more to precipitate. In cases of extreme heat this water may supersaturate the environment and cause precipitation with even the slightest cooling. People in states along the gulf coast know this effect as their daily afternoon thunderstorms. This case of global supersaturation causes extreme precipitation in regions where temperature gradients are extreme. Texas is a good example. Very warm weather and fairly flat land allows moisture to migrate inland before precipitating when the air temperature drops in the evening. The flatter land also causes the water to be retained and cause localized flooding even though there is little local water. The same effect is being seen across the world. England is flooding, the Western untied States is in severe drought (wanna bet the oversaturated clouds are dumping their moisture before they reach these ares?), and of course the Floods in Texas. Now, not all this is due to the lowering surface water accumulations, but it can't be helping.
