The Intergovernmental Panel on Climate Change has issued a report about global warming, identifying the scale of the global warming problem, and some of the impacts. I know that most ordinary people will not read the report (it is huge, and not written for laymen), and will instead get their information from the news and the Internet, so I thought I would put some of the data in perspective.

Most of the predictions are for changes by the year 2050. These are bad enough, but please remember that change will continue after 2050, and by the end of the century the impacts will be even more severe.

If you want to see some of these environmental impacts in more human terms, I recommend two movies: Soylent Green and Silent Running. Please don't dismiss them just because they are "science fiction". The role of serious science fiction is to explore the social, environmental, economic and political consequences of technology and other influences in our world, and in some cases these pieces of fiction do a pretty good job of predicting.

Changes in Crop Yields

Most parts of the world will get warmer, and some parts will get wetter. This will have dramatic impact on crop yields, which will vary from place to place.

The first graphic in this story shows the predicted change in gross crop yields around the world. There are are some places (Canada, Scandinavia, Eastern Europe New Zealand, and Russia) where yields are expected to increase, but these predictions do not take into account the changes in crop pests due to climate change. Most of the world will see reduced yields (including the USA, a major food exporter). Crop yields for maize, rice and wheat are all expected to be reduced in the period up to 2050, with some projections showing losses over 25%.

Some agricultural land will become non-arable or only marginally arable.

One thing that this picture doesn't make clear is that crop species will have to change is some countries to adapt to the changed climate. This will mean changes to the diets of billions of people.

Food will get more expensive, and there will be shortages. Also, expect that more of your food will come from intensive farming rather than wild or natural sources (less free-range eggs, more GM food, farmed fish and vegetables grown under glass).

Pests and Diseases

Already we are seeing changes to the distribution of crop pests and diseases. This will get worse. Expect to see tropical diseases like malaria, dengue fever and yellow fever spreading in Europe and North America. Expect to see more invasive diseases amongst wild species (e.g. lethal tree fungus) in places like Britain. Expect more invasions of scorpions, ants, termites, hornets, etc.

As a result, expect there to be more need to control such pests (with resulting increases in the use of pesticides), and inoculations for a wide range of diseases becoming standard in many countries.

Weather

There are already many parts of the world where outdoor temperatures reach hazardous levels: especially Africa and the Middle East. For those of us who don't tolerate high temperatures well, there will be increased risk of heat-stroke, and there will be an increase in the rate of temperature-related deaths of building workers in some countries.

All this will increase the costs, and decrease the productivity, of outdoor work (agriculture and building). Air-conditioning (itself a contributor to global warming) will become more necessary for office work around the world.

In some regions there will be major increases in rain (and snow), and increases in flooding. In others there will be less rain, with associated desertification. There will be more extreme weather: thunderstorms, tornadoes, typhoons/hurricanes, and high winds. There will be increases in the rate of erosion of coastlines in many regions.

The permafrost is already melting in parts of Russia and North America (making some land impassable, and releasing methane – a strong greenhouse gas).

The Oceans

Sea levels are already rising, and this will continue; how much is not yet clear. Low lying areas (like the Eastern seaboard of the USA) will see significant loss of land. Some nations may choose to introduce dykes and other expensive measures to protect coastlines, meaning the loss of natural coastlines.

Coral reefs are being killed by increased acidity (caused by dissolved CO2) and temperature. Coral reefs are key breeding grounds and food sources, and their loss will impact the whole oceanic ecosystem,.

As temperatures change, fish populations will need to adapt by changing their geographical ranges, moving nearer the poles. Such migrations are not without their risks, and some populations will not succeed; other fisheries will suffer significant loss of productivity as they migrate. Migratory species (eels – already in decline – salmon, sea trout and tuna) are likely to find it particularly hard to adapt their ranges in response to climate pressures. So, not only will seafood availability change to new locations, but there will be a (hopefully temporary) did in fishery productivity.

Changes in fishery locations and productivity will have huge impacts on dependent will species: whales, dolphins, seals, and seabirds.

Fresh Water

Fresh water supplies (for drinking and washing) are already in short supply in much of the world. As rainfall patterns change, and many parts of the world become more arid, this will get much worse. Water rationing (already common in some areas) will become more common for many people. Even in countries which have enough water, the lack of national water grids mean that water is often not available where it is needed, and this can be expected to get worse.

The increased costs of water will make crop irrigation prohibitively expensive for some (e.g. in California). This will impact food price and availability, and the economies of some areas.

Clean water is a key enabler for hygiene, and water shortages will have side-effects on the health of populations and the spread of diseases like cholera and typhoid.

Migration

The report predicts that there will be increased migrations of people due to climate change.

Migration brings with it all the usual associated political and social problems. Migrants are usually not welcome at their destination, and are often barred from entry into new countries. Across the world there are existing issues with migrations, whether actual or attempted: Mexicans and Filipinos entering the USA, refugees from the war in Syria and Africa trying to get into Europe, and migrants from Asia trying to enter Australia. The creation of new waves of economic migrants trying to enter richer countries will not be any better received, even if the root cause is pollution caused by those same richer nations.

Wildlife

Species loss will continue, and indeed accelerate; lost species can never be replaced, and extinction is the worst crime that the human race has perpetrated on the natural world.. This will mean loss of genetic diversity, and result in more risks to food security (wildlife is still a key source of genetic material to enhance crops with pest resistance and improved yields).

There will generally be less wildlife around us. Those of us who love walks in the woods, scuba diving, fishing, hunting and other activities that bring us close to nature are going to be disappointed.

Whilst many fish, birds and human beings can migrate to adapt to the changed world, land-based wildlife cannot migrate so easily anymore. There are many natural and man made barriers to wildlife migration. Large mammals will be especially hard hit, but extinctions will be very high amongst all land based wildlife.

Similarly, due to the lack of truly wild and unoccupied land, and their lack of mobility, plants will be largely unable to migrate, and many extinctions will occur.

War

The human race has well established techniques for dealing with lack of resources (water, food, energy resources and uneven wealth distribution): war. Just look at today's world, and at recent history: Israel/Palestine (about land and water), Iraq (invaded, many argue, because of oil), Sudan (originally perhaps an ethic issue, but now about oil), UK/Iceland (the cod wars), and China versus the rest of South-East Asia (the islands, through which control of oil and fisheries are decided).

I don't have high hopes that the human race is suddenly going to grow up in the next few years.

That means that we should expect that climate change caused by global warming will be the trigger for more war, and probably the root cause of much terrorism (as in Nigeria, where at least some of the terrorism is about oil revenues). From a distance, it is going to look really stupid, since war is horribly polluting and will only exacerbate the problem of global warming.

The prospect of us fighting over the last scraps of food and water, to the point where we, and 99% of the species with whom we share (not so graciously) the planet, become extinct, does not seem so implausible now. I do hope that at least this one prediction, made in so many science fiction movies and books, is wrong.