Why we need new climate models

Why we need new climate models
The higher the resolution, the more precise the forecasts: climate models. Credit: ETH Zurich

Climate models are a success story, given that much of what they predicted has actually come true. Nevertheless, Reto Knutti points out in a blog post, researchers still need new models.

In 1950, meteorologists Jule Charney and Ragnar Fjørtoft joined with mathematician John von Neumann and other researchers to create the first computer simulation of the weather. Back then, it took 24 hours of calculations to forecast 24 hours' worth of weather. In other words, practically as soon as the paltry forecast was finished, reality had set in and rendered it useless. Today's weather forecasts are astoundingly good, often producing skillful forecasts up to a week in advance and designed to include extreme events. They are available on every mobile phone and everyone knows how to interpret them.

Amazing progress of climate models

Climate models are closely related to ; and they, too, have made amazing progress. Today they simulate air and ocean currents, sea ice, the biosphere, land, the carbon cycle and much more. They take into account thousands of feedback effects and processes, consist of a million lines of programming code, and produce petabytes of data—and these models are a success story in many ways. Many climate projections have come true. It was on the basis of just such projections that policymakers decided we should limit anthropogenic global warming to considerably less than 2 degrees Celsius. But why, then, does this field require even more research and new models?

Decades ago, statistician George Box stated: "All models are wrong, but some are useful." And indeed, every model simplifies reality to some extent. For certain questions, this simplification is justified, while for others, the uncertainties are still great. One point in particular is that each model has a specific spatial resolution, or scale, beneath which no forecasts are possible. Nowadays typically have a scale of 10 to 50 kilometers. Even this resolution makes it clear that we need to reduce our CO2 emissions. However, to find out how frequently hot and dry summers such as the one in 2018 will occur, or if the Swiss mountain village of Sedrun will still receive enough snow in the year 2040, we need a scale of just a few kilometers. This is because mountains, valleys and highly localized phenomena—such as the rising of air masses that turn into cloud formations—play critical roles.

Yet achieving these smaller scales requires enormous computing power, the likes of which is found more and more frequently only in computers with graphics processing units (GPUs). Therefore, the model's "inner workings," in other words how the individual cores share and process data, have to be reprogrammed. Such powerful supercomputers make it possible to map small-scale phenomena, such as thunderclouds, or city models in new and improved ways. However, they also produce more data than can possibly be stored.

Getting a high-resolution model to run on a new computer architecture thus requires the expertise of physicists, chemists, biologists and other experts to better describe these small-scale phenomena. Computer scientists, too, are needed if we are to make efficient use of the new technologies. But at the end of the day, even the best simulation is useless if its users don't understand it or don't know what to use it for.

Benefits to society

For researchers, climate models are tools with which they can test their hypotheses, learn to understand processes and interpret measurement data. But they can also do more: climate models are used in forecasts to minimize the risks and vulnerabilities of society and infrastructure and to find robust means of adjustment. The dialog with and benefit for users is key to this process. Once we climate modelers understand what information farmers or civil engineers need for what place and time frame, then we can better prepare our models for adjustment—a shining example of how technological development and inter- and transdisciplinary research work together to deliver tangible benefits to society.


Explore further

Existing climate models useful in forecasting, model testing

More information: E. M. Fischer et al. Observed heavy precipitation increase confirms theory and early models, Nature Climate Change (2016). DOI: 10.1038/nclimate3110
Journal information: Nature Climate Change

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Citation: Why we need new climate models (2019, August 21) retrieved 21 September 2019 from https://phys.org/news/2019-08-climate.html
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Aug 21, 2019
Climate models are a success story, given that much of what they predicted has actually come true.

Ha ha ha HAAAA!!! Thank you! I needed the laugh.

Just for the record, nothing the CMIP models has predicted has "come true". They are utterly useless for prediction. You're better off examining sheep entrails. Even the vaunted IPCC illustrated this in their Fifth Assessment Report in 2013. See this graph of temperature projections against observations:

https://www.ipcc....14-3.jpg

That black line is measured temperatures. The multi-color spaghetti lines above it are the computer projections. Notice how they all predict more warming (much more) than actually happens?

Here's the interesting thing. Like Reto Knutti, millions devoutly believe the climate models and their predictions are accurate even when they are demonstrably not. All the dire predictions are based on the failed models. Reality, however, is unremarkably benign.

Aug 21, 2019
Climate models are a success story, given that much of what they predicted has actually come true.

When reality defies your blatant lies, what is a desperate AGW Cult to do?
Well, resort to comedy, of course.

LMAO.

Aug 21, 2019
@assdad and @tehgeighalgore hate climate.

Aug 21, 2019
When reality defies your blatant lies, what is a desperate AGW Cult to do?
Well, resort to comedy, of course.

LMAO.
Models are quite useful for all kinds of things, it's one of the things scientists do regardless of which branch of science it is. Serious business, nothing comedic about it for critical thinkers.

Aug 21, 2019
Newton's and Galileo's models changed the course of human history.

Apparently antiscience freaks don't like that.

Aug 21, 2019
When reality defies your blatant lies, what is a desperate AGW Cult to do?
Well, resort to comedy, of course.

LMAO.
Models are quite useful for all kinds of things, it's one of the things scientists do regardless of which branch of science it is. Serious business, nothing comedic about it for critical thinkers.

Well, a critical thinker you most certainly are not. But, at least your response is funny.

LMAO.

Aug 21, 2019
@tehgeighalgore hates Galileo and Newton.

Aug 21, 2019
I don't happen to have the report in front of me, but I believe it was the IPCC's Fourth Report that included: "Climate is a non-linear chaotic (?) system that cannot be modeled", and their reports are the 'gold standard' of research.

Aug 21, 2019
Another liar denier blocked. Why do you people keep trying? It's not going to work.

Aug 22, 2019
UN's Climate Science Body Admits Predicting Future Climate 'NOT POSSIBLE'

https://principia...ossible/

https://www.quora...possible

Aug 22, 2019
@antigoracle @aksdad well, I think you guys have a hard reading the graphs. In what you peeps linked, the outcome sits within the mean and follows the projected patterns. The mean does increase over time, and it is being confirmed. The deniers have a legitimate issue with people that only use the high end numbers, but, those individuals also have an axe to grind. What I don't get is how deniers just ignore the reports conducted by oil companies, where the scientists were on a contract and had nothing to gain by "perpetrating a hoax".

By the way, how much do you guys (professional deniers) get paid now a days? Rumor is you guys received a paycut, is that true?

Aug 22, 2019
BLAH...BLAH....BLAH..What I don't get is how deniers just ignore the reports conducted by oil companies, where the scientists were on a contract and had nothing to gain by "perpetrating a hoax".

By the way, how much do you guys (professional deniers) get paid now a days? Rumor is you guys received a paycut, is that true?

Uh huh. What I don't get is you Chicken Littles believe burning oil will destroy the world, yet you continue paying those evil oil companies for the privilege.
BTW, how much of the AGW Cult's bullshit can you guys eagerly swallow and pack in the space between your ears? Fact is, it's unlimited. True?

Aug 28, 2019
@antigoracle.

What is it about 'transitioning' from fossil fuels to green renewables that escapes you? They also still rode horses until the 'transitioning' from horses to motor vehicles and trains was completed. The same will happen once the transitioning from fossil to renewables is completed. Which transition is under way as we speak...accelerating along with the the advances in green renewables-power and motor vehicles production/uptake; as the cost of transitioning gets less and less; and the benefits increase (ie, less pollution; less climate disasters; less traffic noise; etc). Wake up to yourself, mate. :)

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