Climate change predictions — what went wrong?

By Paul Homewood

 

 

A good analysis in the Times, following up last week’s story about how climate models had grossly overestimated global warming:

 

 

As egg-on-face moments go, it was a double-yolker. Last week a group of climate scientists published a paper that admitted the estimates of global warming used for years to torture the world’s conscience and justify massive spending on non-carbon energy sources were, er, wrong.

 

Being wrong is not a criminal offence, especially in science, where in the long run almost everything turns out to be wrong, but the global warmers have adopted such a high-and-mighty tone to anyone who questions them that for sceptics this was pure joy.

The world may still be doomed, but it is not quite as doomed as the climatologists have repeatedly told us.

The admission was overdue acknowledgment of something that has been obvious for years. Despite the climate models predicting rapidly rising temperatures, between 1998 and 2013 temperatures barely rose at all. This was a pause, not a change in the underlying trend, the scientists and the Intergovernmental Panel on Climate Change insisted. Global warming was still going on, even when it wasn’t.

The pause hadn’t been predicted by the computer models, but admitting that wasn’t really an option. Anxiety needed to be ramped up in order to achieve international agreement on cutting carbon emissions. That was achieved — at the cost of browbeating doubters — and the Paris agreement struck in 2016 committed signatories to limit warming to 1.5C above pre-industrial levels.

It couldn’t actually be done, the scientists said. To keep warming below 1.5C, total emissions from 2015 onwards could not amount to more than 70 gigatonnes of carbon — seven years’ worth at current emission rates.

Last week’s paper in Nature Geoscience recalculates that as 200 gigatonnes, or 240 gigatonnes if great efforts are also made to reduce other global-warming gases such as nitrous oxide and methane.

So instead of seven years, we’ve got 20, or maybe 24. The task has gone from impossible to very difficult, said one of the paper’s authors, Joeri Rogelj.

Another author, Myles Allan of Oxford, told The Times: “We haven’t seen that rapid acceleration in warming after 2000 that we see in the models. We haven’t seen that in the observations.”

Allan’s defence of the models, however, was peculiar. He said that they had been assembled a decade ago, so it wasn’t surprising they had deviated from reality. Yet these are the very same models used to make predictions for 50 or 100 years ahead which have saddled taxpayers with huge costs to pay for alternative energy sources. Anybody who doubted their predictive power was labelled an unscientific dolt, a “climate denier” fit to be listed with the Flat Earthers.

As long as there have been computer models, there have been inaccurate forecasts. In the early 1970s the Club of Rome published The Limits to Growth, an extrapolation of population, pollution and resource depletion that concluded that the world was heading for imminent catastrophe. It sold more than 16m copies. I keep one on my shelves to remind me of the folly of Malthusian predictions.

Today the world is richer, cleaner, and better-fed than it was in 1972, while the Club of Rome is forgotten. It still exists, headquartered in Winterthur, Switzerland, which must be nice.

The global-warming models are far more sophisticated than the Limits to Growth model, but that isn’t entirely a good thing. There is a paradox in modelling: the more sophisticated the models become, the greater the uncertainty of the effects they predict. As more parameters are added to the models — the rate at which ice falls through clouds, for example — the more uncertainties are added.

To reach its conclusions in the new paper, the team used actual temperatures today, which are 0.3C lower than the models said they would be. That provides more headroom for carbon emissions before the 1.5C target is reached. While the models’ error may seem small, it has big implications for future policy.

For one thing, it makes President Donald Trump’s rejection of the Paris agreement far less worrying. The US emits about 1.5 gigatonnes of carbon a year. Supposing Trump serves only a single term and in that time America reduces mitigation efforts, the effect is going to be insignificant when compared with the 200 gigatonnes the team estimates the world can afford to emit.

However, what the climate-change campaigners fear is that the acknowledgment of error will take the pressure off. Two of them, Lord Stern and Lord Krebs, wrote to The Times to try to head this off.

They argue that the errors do not mean that climate change isn’t happening. There were always uncertainties about its pace and magnitude, Krebs says — though you might not have thought so from the language often used and the efforts to deny airtime to those with doubts, such as Lord Lawson, the former chancellor.

Warming resumed in 2014. The climate warmers aren’t wrong, though a touch more humility would be appreciated.

https://www.thetimes.co.uk/edition/news-review/climate-change-predictions-what-went-wrong-78ckkbx2f

 

Unfortunately the author spoils things with his final sentence. As we know, in 2014 temperatures began to spike as a result of the record El Nino.

Since late last year they have returned earlier levels. The pause is alive and well!

http://www.drroyspencer.com/latest-global-temperatures/

 

There has been a desperate attempt to divert attention away from the findings of the new paper. This article mentions a letter to the Times by the phoneys, Lords Krebs and Stern.

I have also seen a similar letter in the Mail from Myles Allen. It stated that the difference of 0.3C was really rather insignificant, and that we were still all going to die if we did mend our evil ways, only slightly later!

But the difference is actually really huge, bearing in mind that this is over a period of just 15 years, and particularly when the authors admit that emissions of CO2 have been much greater than originally assumed.