The fact that heat waves like the one in Russia become more frequent and extreme in a warmer world is easy to understand. Extreme rainfall events will also become more frequent and intense in a warmer climate, owing to another simple fact of physics: warm air can hold more moisture. For each degree Celsius of warming, 7% more water is available to rain down from saturated air masses. Drought risk also increases with warming: even where rainfall does not decline, increased evaporation dries out the soils.
类似俄罗斯那样的热浪在变暖的世界里更加频繁且极端恶劣这一事实不难理解。由于另一个简单的物理学事实，即暖空气能容纳更多的水汽，在比较暖和的气候中，极端降雨事件也会变的更频繁、更剧烈。气温每上升1摄氏度，饱和大气团中可降的雨水就会增加7%。干旱的隐患也会随着气候变暖而增加：即使是在降雨量没有减少的地区，蒸发量的增强也使土壤变干了。
