Global warming has benefits, as well as costs
Matt Ridley blogs:
Global warming is real. It is also – so far – mostly beneficial. This startling fact is kept from the public by a determined effort on the part of alarmists and their media allies who are determined to use the language of crisis and emergency. …
The biggest benefit of emissions is global greening, the increase year after year of green vegetation on the land surface of the planet. Forests grow more thickly, grasslands more richly and scrub more rapidly. This has been measured using satellites and on-the-ground recording of plant-growth rates. It is happening in all habitats, from tundra to rainforest. In the four decades since 1982, as Bjorn Lomborg points out, NASA data show that global greening has added 618,000 square kilometres of extra green leaves each year, equivalent to three Great Britains. You read that right: every year there’s more greenery on the planet to the extent of three Britains. I bet Greta Thunberg did not tell you that.
The cause of this greening? Although tree planting, natural reforestation, slightly longer growing seasons and a bit more rain all contribute, the big cause is something else. All studies agree that by far the largest contributor to global greening – responsible for roughly half the effect – is the extra carbon dioxide in the air. In 40 years, the proportion of the atmosphere that is CO2 has gone from 0.034 per cent to 0.041 per cent. That may seem a small change but, with more ‘food’ in the air, plants don’t need to lose as much water through their pores (‘stomata’) to acquire a given amount of carbon. So dry areas, like the Sahel region of Africa, are seeing some of the biggest improvements in greenery. Since this is one of the poorest places on the planet, it is good news that there is more food for people, goats and wildlife.
Fascinating. I did not know this. It shouldn’t be surprising, as changes in climate always have positive and negative aspects to it.
Another bit of good news is on deaths. We’re against them, right? A recent study shows that rising temperatures have resulted in half a million fewer deaths in Britain over the past two decades. That is because cold weather kills about ’20 times as many people as hot weather’, according to the study, which analyses ‘over 74million deaths in 384 locations across 13 countries’. This is especially true in a temperate place like Britain, where summer days are rarely hot enough to kill. So global warming and the unrelated phenomenon of urban warming relative to rural areas, caused by the retention of heat by buildings plus energy use, are both preventing premature deaths on a huge scale.
Surely this will change in the future? Probably not. Britain would have to get much, much hotter for summer mortality to start exceeding winter deaths. Not even Greece manages that. And the statistics show that – as greenhouse-gas theory predicts – on the whole more warming is happening in cold places, in cold seasons and at cold times of day. So winter nighttime temperatures in the global north are rising much faster than summer daytime temperatures in the tropics.
This doesn’t mean a huge increase in temperatures will be beneficial. What the data shows is that the changes so far have resulted in fewer climate related deaths. There is of course a tipping point at which heat deaths would exceed cold deaths.
Of course, climate change does and will bring problems as well as benefits. Rapid sea-level rise could be catastrophic. But whereas the sea level shot up between 10,000 and 8,000 years ago, rising by about 60 metres in two millennia, or roughly three metres per century, today the change is nine times slower: three millimetres a year, or a foot per century, and with not much sign of acceleration.
All the forecasts are that the current rate of 3mm/year will increase but so far it hasn’t. Here’s the increase for each five year period:
- 1990 – 1995: 8 mm
- 1995 – 2000: 7 mm
- 2000 – 2005 : 11 mm
- 2005 – 2010: 21 mm
- 2010 – 2015: 18 mm
- 2015 – 2020: 7 mm
So since 2005 it has increased 46 mm in 15 years which is 3 mm a year.