By now a lot of people are probably getting sick of hearing about climate change, but it needs to be continuously emphasized because the problem is not going away any time soon. People are now starting to realize that global warming means stronger storms, but that is the least of our problems. Worse than that, most people don’t actually know what many of our problems are going to be. Let us forget about storms and look at what else could happen.
The most frightening is if warming gets out of control and melts the Arctic tundras. We have to be careful about this, but we know that about 252 million years ago there was the most massive mass extinction ever. What happened? We cannot be entirely sure, but one account has it that global warming of about four degrees caused the release of Arctic methane, and 97% of life on Earth died. Now, of course we cannot be sure of what happened and the Earth is not like what it was then. The continents are not even the same, and those land forms that were there then are not in the same place now. Nevertheless, we can be sure that if the Arctic methane is released due to warming, there will be a very serious enhancing of temperature. Amongst other things, for the first two decades methane is 87 times worse than carbon dioxide.
The most obvious consequence is from the heat. Already there are parts of the world where heat becomes a problem for people working, and this is not helped by humidity increases. In 2003 there was a European heat wave that killed as many as 2000 people every day it maintained its high temperatures. If we add 2 degrees to the average temperatures, cities in the middle east, like Bahrain, and further east like Karachi and Kolkata will be almost uninhabitable, and for Muslims, the hajj would be impossible. We could try air conditioning, but with what fuel? Our current energy systems would simply add to the problem.
Warming of agricultural areas reduces crop yields. At present, most crops are grown in as near ideal conditions for them, and most foods are produced in quantities to feed the population, but not with a huge excess. So the biggest problem is starvation. You may say, move the agriculture away from the equator to newly warmed regions. That is possible to some extent, but what we forget is that the current colder regions do not have good soil. Trying to grow crops in Greenland is fine, until you discover that most of the newly exposed surface is stone.
There are also secondary issues, thus the recent flooding in Bangla Desh that covered almost half the country with water also largely destroyed the crops being grown there. Other places may suffer droughts, with the same result. My view is this is uncertain, because I do not believe that modeling is good enough. You will hear that in Jurassic times temperatures were significantly warmer than now. Yes, but much of the land was desert, the continents were also in a greatly different configuration, and mammals were not predominant.
Everyone now knows that as the ice melts, the sea levels will rise. Depending on how much ice melts, the seas could rise by seventy meters. At present, about 600 million live within ten meters of sea level. Given that even modest sea level rising predicts a seven to fourteen meter rise, you can see that an awful lot of infrastructure will have to be rebuilt, and perhaps a billion people moved and rehoused, followed by somehow finding them employment. That means more carbon dioxide emissions. Cement manufacture alone produces about three billion tonne of carbon dioxide per annum now, and if we have to rebuild the entire coastal infrastructure, a huge amount of additional cement will be required. If the sea absorbs too much carbon dioxide, and a lot of organic matter gets trapped in it, parts may go anoxic and emit large amounts of hydrogen sulphide. Excessive hydrogen sulphide is the agent that is believed to have enhanced the great extinction in the late Permian. Higher levels of carbon dioxide are often used to explain coral bleaching, but the problem is much worse. Shellfish that depend on aragonite, one of the two crystalline forms of calcium carbonate, will not be able to form shells if the oceans absorb significantly more carbon dioxide because aragonite will no longer crystallise.
The removal of ice from the poles will also alter weather patterns. Wind changes may lead to greater air pollution in certain areas if we try to maintain current industries. China has recently suffered from this. Places that are now livable will become desert, or near desert, and this will force people to move. The problem, is, where to? Where will they get work? Which countries are going to accept them, particularly bearing in mind the numbers also displaced from the shores? With few options, various wars are more likely to break out. Unless we solve the energy crisis, what next? If we stop burning fossil fuels, how will our economies progress? The real driver of economic growth since the mid 19th century has been cheap energy from fossil fuels. However, if we do not stop such burning, and if we do not find alternatives, GDP will drop significantly, which will make it more difficult for a large fraction of the population to earn a living. To survive, one outcome is enhanced war and a proliferation of crime.
Scary? Hopefully these consequences are sufficient to persuade those in power to do a lot. I am far from convinced that current politicians recognize what the problem even is, let alone how to address it.