After covering global warming ­debates as a journalist on and off for almost 30 years, with initial credulity, then growing scepticism, I have come to the conclusion that the risk of dangerous global warming, now and in the future, has been greatly exaggerated while the policies enacted to ­mitigate the risk have done more harm than good, both economically and environmentally, and will continue to do so.
And I am treated as some kind of pariah for coming to this conclusion. Increasingly, many people would like to outlaw, suppress, prosecute and censor all discussion of what they call “the science” rather than engage in debate. We’re told that it’s impertinent to question “the science” and that we must think as we are told. But ¬≠arguments from authority are the refuge of priests.
These days there is a legion of climate spin doctors. Their job is to keep the debate binary: either you believe climate change is real and dangerous or you’re a denier who thinks it’s a hoax. But there’s a third possibility they refuse to ¬≠acknowledge: that it’s real but not dangerous. That’s what I mean by lukewarming, and I think it is by far the most likely prognosis.
I am not claiming that carbon dioxide is not a greenhouse gas; it is. I am not saying that its concentration in the atmosphere is not increasing; it is. I am not saying the main cause of that increase is not the burning of fossil fuels; it is. I am not saying the climate does not change; it does. I am not saying that the atmosphere is not warmer today than it was 50 or 100 years ago; it is. And I am not saying that carbon dioxide emissions are not likely to have caused some (probably more than half) of the warming since 1950. I agree with the consensus on all these points.
Some of my scientific friends accuse me of inconsistently agreeing with the scientific consensus that genetic modification of crops is safe and beneficial, but refusing to agree with the scientific consensus that climate change is dangerous. I agree with the scientific consensus on GM crops not because it is a consensus but ¬≠because I’ve looked at sufficient evidence. There is no consensus that climate change is going to be dangerous. Even the UN Intergovernmental Panel on Climate Change says there is a range of possible outcomes, from harmless to catastrophic. I’m in that range: I think the top of that range is very unlikely. But the IPCC also thinks the top of its range is very unlikely.
Besides, consensus is a reasonable guide to data about the past but is no guide to the future and never has been. In non-linear systems with feedbacks, like economies or atmospheres, experts are notoriously bad at forecasting events. There is no such thing as an expert on the future.
It is undeniable that the ¬≠climate models have failed to get global warming right. As the IPCC has confirmed, for the period since 1998, “111 of the 114 available climate-model simulations show a surface warming trend larger than the observations”. That is to say there is a consensus that the ¬≠models are exaggerating the rate of global warming.
The warming has so far resulted in no significant or consistent change in the frequency or intensity of storms, tornadoes, floods, droughts or winter snow cover. The death toll from droughts, floods and storms has been going down dramatically. Not because weather has got safer, but because of technology and prosperity.
As two climate scientists, Richard McNider and John Christy, have put it, “We might forgive these modellers if their forecasts had not been so consistently and spectacularly wrong. From the ¬≠beginning of climate modelling in the 1980s, these forecasts have, on average, always overstated the ¬≠degree to which the Earth is warming compared with what we see in the real climate.”
In 1990, the first IPCC assessment predicted a temperature ­increase of 0.3C per decade (with an uncertainty range of 0.2C to 0.5C). In fact in the 2½ decades since, even though emissions have risen faster than in the business-as-usual scenario, the temperature has risen at an average rate of about 0.15C per decade based on surface measurements, or 0.12C per decade based on satellite data; that is, less than half as fast as ­expected and below the bottom of the uncertainty range!
What about 2015 and 2016 both being record hot years? Well, because of the massive El Nino, the HADCRUT4 surface temperature line just about inched up briefly in early 2016 into respectable territory in among the lower half of the model runs for a few months before dropping back out again. That’s all.
So why is the atmosphere not doing what it is told? Actually it is. These results are precisely in line with the physics of the greenhouse effect. A doubling of CO2 in the atmosphere cannot on its own produce dangerous warming. The sensitivity of the atmosphere to CO2 is about 1.2C per doubling. That is the consensus, spelled out clearly (if obscurely) by the IPCC several times over the years. And that’s what we are on course for at the moment.
So what is the problem? Well, the theory of dangerous climate change depends on a whole extra step in the argument — the ¬≠supposed threefold amplification of carbon dioxide’s warming ¬≠potential, principally by extra water vapour released into the ¬≠atmosphere by a warming ocean, and accumulating at high altitudes. And the evidence for that is much more shaky.
Recent attempts to measure the sensitivity of the climate system to carbon dioxide using real data nearly all find that it is much lower than the models assume. So, if it’s consensus that floats your boat, there is an emerging consensus from observational estimates that climate sensitivity is low.
What’s more, all the high estimates of warming are based on an economic and demographic scenario called RCP 8.5, which is a very unrealistic one. It assumes that population growth stops decelerating and speeds up again.
It assumes that trade and innovation largely cease. It assumes that the ability of the oceans to ­absorb CO2 fails. It assumes that despite all this the income of the average person trebles. And most absurd of all, it assumes that we go back to using coal for almost everything, including to make motor fuel, so that by 2100 we are using 10 times as much coal as we are today. In short, it is a barking mad scenario.
It is beyond question that global warming has generated enormous research funds, measured in many billions, that this has stimulated all sorts of scientists, from botany to psychiatry, to link their work to climate change, and that almost none of this money flows to those with sceptical views.
As the distinguished NASA climate scientist Roy Spencer has written, “If you fund scientists to find evidence of something, they will be happy to find it for you. For over 20 years we have been funding them to find evidence of the human influence on climate. And they dutifully found it everywhere, hiding under every rock, glacier, ocean, and in every cloud, hurricane, tornado, raindrop, and snowflake. So, just tell scientists 20 per cent of their funds will be targeted for studying natural sources of climate change. They will find those, too.”
