The weather in 2026
Philip Eden
From The World in 2006 print edition
The climate has changed since we first published, in 1986. How will it change over the next 20 years?
“How can you predict what the climate will be like in 20 years’ time when you can’t even get tomorrow’s forecast right?” That is the usual response from the layman to the climatologist expounding the latest theory on climate change.
Put it this way: forecasting tomorrow’s weather is a bit like estimating how much loose change you will have in your pocket or purse in 24 hours’ time. It is the result of many small transactions, often inter-related, most of them entirely predictable at such short range: a visit to the cashpoint, buying groceries, pocket-money for the kids, and so on. Foreshadowing changes in the climate over a long period is more akin to calculating the household budget over a year or more: the daily transactions hardly matter, whereas much more important are out-side influences, many of which are predictable but some of which may be quite unexpected.
Climatologists believe they understand most but not all of these “forcing factors” and are therefore able to make broad-brush, qualified assessments of where the world’s climate may go in coming decades.
We can get a feel for the direction the climate is taking by looking back 20 years. During that period the mean temperature of the lowest layer of the atmosphere, where human beings live, has increased by 0.4°C. The warming has not been even: the northern hemisphere has warmed more than the southern hemisphere, the continents more than the oceans, the polar fringes more than the core of the Arctic and Antarctic, and Europe more than North America. In Europe (excluding the Mediterranean basin) there were twice as many heat-related deaths in two weeks in August 2003 than there had been in the 20 previous years put together. In September 2005 both the geographical extent and the mean thickness of Arctic Ocean ice reached record low levels.
The warming seems to be accelerating. Computer models indicate a rise in temperature, averaged globally, of 0.5-1.0°C between 2006 and 2026. We can expect the hemispheric and continent/ocean differentials to continue, though not necessarily the transatlantic one, so substantial further warming is likely over both Europe and North America.
In the Arctic basin sea-ice may vanish altogether in the summer by the 2020s; this will probably generate a dynamic of its own. For the time being energy in the form of latent heat is absorbed throughout the summer by the melting process in the Arctic, maintaining cold conditions there and preventing the ocean temperature from climbing more than a degree or so above zero. If all the ice were routinely to disappear by late July, that energy absorption would halt, the Arctic Ocean would warm by several degrees, delaying the onset of ice formation in the autumn. The change in temperature distribution in the Arctic would also affect ocean currents in the Atlantic, which would in turn influence the atmospheric circulation in the region.
These knock-on effects are very difficult to model on the computer because we have no detailed measurements from previous such occurrences. However, one could postulate a poleward shift in the Atlantic depression track, and that would leave much of Europe—Scotland, Iceland and Norway excepted—with less rain in all seasons and much more prone to water shortages.
Tropical revolving storms (variously known as hurricanes, typhoons and cyclones) have been regarded as particularly sensitive to a changing global climate. These storms can develop only where the sea-surface temperature exceeds 26°C. Although their frequency has increased sharply, especially in the Atlantic/Caribbean, this may be part of a natural 60-year cycle: there were previous peaks in the 1880s and 1940s. Still, a warming climate will probably result in storms which are both longer-lasting and more intense, and which may develop in areas hitherto largely immune—offshore Brazil, for instance. And although their frequency may decrease between now and 2026 in line with the natural cycle, this may be partly offset by an extension of the season. Remember, too, that the coastal fringes threatened by these storms, from Texas to Taiwan, Florida to the Philippines, are increasingly urbanised and susceptible to huge human and economic losses.
Climate, it was once said, is average weather. That is not so. The climate of a given place is described by the extremes as well as the averages. Even if the world’s climate were static there would be dozens of natural disasters every year. With a rapidly changing climate, the next 20 years will be a white-knuckle ride: droughts, floods, heatwaves and hurricanes will probably occur more frequently (affecting regions that were previously untouched) and be longer-lasting. Even the mundane will change: in 2026 the ordinary day-to-day weather where you live will be different—almost certainly warmer, possibly drier but in other places possibly wetter—than it is today.
. I just can't wait for everyone to start riding horses to work.