The Good News
We should not neglect to make a brief survey of possible positive aspects of global warming. We already mentioned that the warming that ended the Little Ice Age was generally a relief for people suffering from the harsh winters of that period. It is quite likely that the recent rapid expansion of population also was aided by climate change. At the end of the Little Ice Age, amelioration of the climate and the spread of high-yield crop species, together with an expansion of technology, trade, and medical knowledge, prepared the scene for a decrease in mortality rates.
Living on Earth comes with risks, and continued global warming changes the risk structure in as yet poorly understood ways. Global warming affects many people in many nations, and they have little choice in the matter. But many people will be not much affected, especially if they live well above sea level (which could conceivably rise by ameteror so, within the next hundred years). Even those living close to sea level will have time to move to higher shores.
In California, where wetlands have been a favorite place for putting air strips and other developments, lagoons will re-form where these wetlands used to be. A warm climate yields longer growing seasons, and it may make it possible to grow multiple crops in areas now growing only a single crop. Carbon dioxide (as is often pointed out by optimists) is a nutrient favoring plant growth directly, and can compensate for a lack of water. Its greater availability, therefore, could expand croplands into areas with a water shortage. On the whole, it should rain more, with more vapor being dissolved in the warmer air (although evaporation also increases).
Large regions in high northern latitudes might become available for growing crops and only be limited by sunlight. Continued advances in technology will allow us to condition our domiciles in such a way as to feel comfortable, whatever the outside temperature, and continued advances in the medical sciences will allow us to cope with the expansion of tropical diseases. Compared with the unprecedented expansion of human populations, the fact that Earth is warming is decidedly on the second page, as far as changing the Earth's environment.
Finally, for those who fear for Life on Earth itself: the good news is that Earth has experienced situations with much greater extremes than anticipated for the next millennium and has survived many extremely threatening and catastrophic events. It is generally thought that CO2 contents were quite high in the atmosphere in the distant past (say, a hundred million years ago). Apparently one could live quite well at the time, especially as a reptile.