I was in a local restaurant recently looking at absolutely torrential rain, and wondered how many people, seeing that, thought "global warming". Certainly a few years ago people were merrily predicting that we would be seeing a mediteranean climate of warm dry summers and cold (dry) winters, but in my mind that was never going to happen.
What global warming really means is more energy in the biosphere, trapped from leaving into space again by additional "greenhouse" gasses. While yes, this may at times translate into noticeably higher temperatures, it will also mean:
- additional evaporation from bodies of water, meaning more cloud and rain;
- higher temperature differentials possible between parts of the atmosphere, enabling faster winds, and larger storms, hurricanes and tornadoes (even in the UK);
- faster transpiration from plants, meaning the ground will dry out faster, possibly cracking or subsiding in the process;
As you will see, several of these trends are towards weather that is less favourable to our current way of life. And several have already started to happen.
Recently, scientists have started to wonder if we should stop saying that individual weather events, such as the recent severe flooding in Pakistan, cannot be signals of global warming, and starting to say that unless we can show otherwise, all weather could be signalling it, and trying to put a scale on how much of an effect warming has had. Some of this is becoming reality: it is possible, for example, to take events like the flooding and run weather models with differing initial parameters to show to what extent the flood is a "once in a lifetime event" that happened to take place now, and to what extent its happening now is a result of our (mis)treatment of the globe. As you might expect, this is a very contentious path to take, even for the scientists, and one has to ask: if you do decide it was a result of warming, what then? Do people take to the Court system?
One saying I really hate in conjunction with all this is "save the earth". The Earth has before, and will in future, survive many worse situations. For example, some 60 million years ago in India, the Deccan Traps were being formed by 30 millenia-long volcanic eruptions that poured out 123,000 cubic miles of lava, covering an area similar to that of present-day India. Less than one million years ago the Earth experienced a series of massive ice innundations that rendered most of Northern hemisphere frigid or covered with thousands of feet of ice. Such things happen here. What we humans have become used to in recent times is decidedly not the norm. Worse, we have become dependent on this "not the norm" state. Our population has grown so much that we can only feed ourselves if things continue to go as we would like, and fresh water supplies are already an issue for around 30% of the worlds population. What we should be saying is "save humanity". That would be much more apposite.