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Science recommends climate model restart

(17 Posts)
thatbags Fri 11-Jul-14 07:38:58

Science, the journal of the American Association for the Advancement of Science, recommends that climate modellers do a restart because current climate models "are not effective at forecasting either future or past temperatures" and for a few more interesting reasons about the cyclicity of climate changes.

hildajenniJ Fri 11-Jul-14 08:04:07

My DD and I once saw a documentory on TV about climate change which predicted that in as little as 30 years we could be in the throes of a mini ice age like the one in the seventeenth century. No-one else I've ever spoken to saw it but the way it was explained was very plausible. This must have been at least ten years ago, so if we're still around in twenty years, we could all be rather cold sad.

FlicketyB Fri 11-Jul-14 11:59:05

In the 1970 and 80s, the possibility of a new ice age was seriously and widely discussed. This theory was current when we had the baking summer of 1976, to much hilarity.

That we are going through a major period of climate change at the moment is undeniable - and that change is leading to hotter and more extreme weather is also undeniable. Where I still remain unsure is about what the causes are. As this article shows the simplistic carbon dioxide causes global warming scenario is far more complex and nuanced than generally made out.

However I do not think that that is a good reason for shrugging global warming off as something that we cannot control and can do nothing about. We know carbon dioxide can contribute to atmospheric warming, even if not as much as previously thought, so there is no advantage to making a difficult climate situation worse and we should do all we can to continue to reduce man-made carbon dioxide emissions.

We all so need to continue to develop non-hydro carbon based fuel technologies, although the date for peak oil and gas production keeps being moved onwards, eventually it will be come a scarce resource so it is better that we use it less greedily for fuel purposes and allow its use to become more and more for the production of petrochemicals and industrial use (non enrgy use).

thatbags Fri 11-Jul-14 13:36:20

Actually, flick, "that change is leading to hotter and more extreme weather", to quote your post, IS deniable. Here are quotations from the last IPCC summary reports, published earlier this year (my bold):

“Overall, the most robust global changes in climate extremes are seen in measures of daily temperature, including to some extent, heat waves. Precipitation extremes also appear to be increasing, but there is large spatial variability”

“There is limited evidence of changes in extremes associated with other climate variables since the mid-20th century”

“Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century … No robust trends in annual numbers of tropical storms, hurricanes and major hurricanes counts have been identified over the past 100 years in the North Atlantic basin”

“In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale”

“In summary, there is low confidence in observed trends in small-scale severe weather phenomena such as hail and thunderstorms because of historical data inhomogeneities and inadequacies in monitoring systems”

“In summary, the current assessment concludes that there is not enough evidence at present to suggest more than low confidence in a global-scale observed trend in drought or dryness (lack of rainfall) since the middle of the 20th century due to lack of direct observations, geographical inconsistencies in the trends, and dependencies of inferred trends on the index choice. Based on updated studies, AR4 conclusions regarding global increasing trends in drought since the 1970s were probably overstated. However, it is likely that the frequency and intensity of drought has increased in the Mediterranean and West Africa and decreased in central North America and north-west Australia since 1950”

“In summary, confidence in large scale changes in the intensity of extreme extratropical cyclones since 1900 is low”

In short, there is no good evidence that global warming is causing more extreme weather.

FlicketyB Fri 11-Jul-14 16:11:23

Global warming doesn't mean homogenous warming and extreme events worldwide.

I quote from your response 'Overall, the most robust global changes in climate extremes are seen in measures of daily temperature, including to some extent, heat waves'. This what global warning is about. What other effects it has on the weather may be more arguable but throughout Europe there have been enough individuals and scientists making weather measurements for long enough for discussions on weather extremes to be robust, even if figures from elsewhere in the world may be more problematic. In Europe we have seen weather records broken again and again over the last 25 years.

I fully accept that the subject should be constantly re-examined and models recalibrated and superseded in the light of increased knowledge but in the mean time I think it is wise to continue to err on the side of caution and as I said in my last post there are very good economic and future supply considerations to make it necessary for us to reduce the proportion of hydrocarbons used to produce energy and to reserve them for the manufacture of industrial chemicals that underpin industry world wide.

thatbags Fri 11-Jul-14 16:54:30

I hadn't come across that definition of climate change before, flick, that one on the second and third lines of your post.

As you say, the encouraging thing is that science journals like Science are finally admitting publicly that the current global climate models don't really work. Let's hope they really are restarted and that their predictions can actually be tested against observations both past and present.

durhamjen Fri 11-Jul-14 17:08:58

I do not like the idea of a restart in the science of global warming, as if the past hasn't happened.
Think tanks keep doing that in lots of spheres, change the parameters and hope nobody notices.

rosequartz Fri 11-Jul-14 18:00:06

I saw it too, Hildajenni

That's what climate does; change.

thatbags Fri 11-Jul-14 19:31:57

The only restart mentioned is of the computer models of climate. There is no mention, nor any idea so far as I know of restarting the science. That's quite an odd idea actually. I can't imagine how such a thing could be done. Not that any scientist would want to. The problem is with the current computer models which do not model what the climate actually does very well. This shows in the divergence between what observations show (observations here being actual scientific measurements of temperature, cloud cover, water vapour in the atmosphere and so on) and what the models predict will happen or has happened in the past. Currently the models are useless as showing what the observations tell us happened in the past so it is unwise to trust them to predict accurately what will happen in the future. The computer models need a restart (or rethink), not the science.

durhamjen Fri 11-Jul-14 19:58:12

But don't they need to keep the historical observations rather than restart?
What they have now is what they thought would happen. Now they think they might be wrong, but they do not know.
They need something for comparison.

rosequartz Fri 11-Jul-14 20:02:22

confused surely they need to keep both models and observations to see how much the original models veered off course - or did not as the case may be?

Ana Fri 11-Jul-14 20:17:52

I'm sure they will keep both for just those reasons, rosequartz. No one's suggesting restarting the science, just the models.

rosequartz Fri 11-Jul-14 20:39:05

Perhaps I need a restart grin

thatbags Fri 11-Jul-14 20:55:42

Of course they need to keep the historical observations. But the observations are actual recorded measurements. The computer models are attempts by programmers to model how the earth's climate system behaves, which is an entirely separate issue from making observations of the climate, measuring climatic things that can be measured, and keeping records of the measurements/observations.

Computer models are not observations. They are interpretations of observations and predictions based on those interpretations and one expectations. Interpretations can be wrong. Observations, one hopes, are accurate. You can't observe snow if it's not snowing but your model might predict that there would be snow (or no snow) and then, when the predicted time came, turn out to be wrong. This has been happening.

I think you might be confusing observations with computer predictions, jend.

rosequartz Fri 11-Jul-14 21:03:33

The models may need a restart but they must not be allowed to discard previous models, they should be used as a reference in future to show how closely or not they were to the actual.

thatbags Fri 11-Jul-14 21:33:44

That sounds like a good idea. Perhaps rewritten (with less limiting parameters) would be a better word in the circumstances than restarted.

thatbags Fri 11-Jul-14 21:34:19

And yes, I do mean less limiting rather than fewer limiting parameters, though the latter might apply too for all I know.