From the “we’re gonna need a bigger computer” department.
Climate model uncertainties ripe to be squeezed
The latest climate models and observations offer unprecedented opportunities to reduce the remaining uncertainties in future climate change, according to a new study.
Although the human impact of recent climate change is now clear, future climate change depends on how much additional greenhouse gas is emitted by humanity and also how sensitive the Earth System is to those emissions.
Reducing uncertainty in the sensitivity of the climate to carbon dioxide emissions is necessary to work-out how much needs to be done to reduce the risk of dangerous climate change, and to meet international climate targets.
The study, which emerged from an intense workshop at the Aspen Global Change Institute in August 2017, explains how new evaluation tools will enable a more complete comparison of models to ground-based and satellite measurements.
Produced by a team of 29 international authors, the study is published in Nature Climate Change.
Lead author Veronika Eyring, of DLR in Germany,said:
“We decided to convene a workshop at the AGCI to discuss how we can make the most of these new opportunties [sic] to take climate model evaluation to the next level”.
The agenda laid-out includes plans to make the increasing number of global climate models which are being developed worldwide, more than the sum of the parts.
One promising approach involves using all the models together to find relationships between the climate variations being observed now and future climate change.
“When considered together, the latest models and observations can significantly reduce uncertainties in key aspects of future climate change”, said workshop co-organiser Professor Peter Cox of the University of Exeter in the UK.
The new paper is motivated by a need to rapidly increase the speed of progress in dealing with climate change. It is now clear that humanity needs to reduce emissions of carbon dioxide very rapidly to avoid crashing through the global warming limits of 1.5oC and 2oC set out in the Paris agreement.
However, adapting to the climate changes that we will experience requires much more detailed information at the regional scale.
“The pieces are now in place for us to make progress on that challenging scientific problem”, explained Veronika Eyring.
From the University of Exeter via press release
The paper: https://www.nature.com/articles/s41558-018-0355-y
Taking climate model evaluation to the next level
Abstract
Earth system models are complex and represent a large number of processes, resulting in a persistent spread across climate projections for a given future scenario. Owing to different model performances against observations and the lack of independence among models, there is now evidence that giving equal weight to each available model projection is suboptimal. This Perspective discusses newly developed tools that facilitate a more rapid and comprehensive evaluation of model simulations with observations, process-based emergent constraints that are a promising way to focus evaluation on the observations most relevant to climate projections, and advanced methods for model weighting. These approaches are needed to distil [sic] the most credible information on regional climate changes, impacts, and risks for stakeholders and policy-makers.
Fig. 1: Annual mean SST error from the CMIP5 multi-model ensemble.
Fig. 2: Schematic diagram of the workflow for CMIP Evaluation Tools running alongside the ESGF.
Fig. 3: Examples of newly developed physical and biogeochemical emergent constraints since the AR5.
Fig. 4: Model skill and independence weights for CMIP5 models evaluated over the contiguous United States/Canada domain.
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since 40 years, min. 2 generations, grabbing breath
“It is believed that this is the case, and that it is a process that is becoming increasingly relevant to model projections. These approaches are needed to distil the most credible information on regional climate changes, impacts, and risks for stakeholders and policy-makers.”
Wasted lives.
If I understand this procedure they are proposing, what they are going to so is take a bunch of disparate models with different assumptions, and collectively having a very wide spread in a range of projected temperatures, precipitation, etc. – then look at the actual temperatures that have been measured and put selective weights in front of the output of each of the models, the weights chosen so that the weighted sum of the models better represents the actual temperatures, precipitation etc. and assume that the weighted group of models better forecasts the future
Assuming that this is a correct restatement, I would simply propose that we call this novel procedure the “Texas Crapshooter Method.”
“When considered together, the latest models and observations can significantly reduce uncertainties in key aspects of future climate change”
Allright then, just back off the CO2 thermostat to match observations.
What? There is no CO2 thermostat in the models? How can it be the control knob in the real world but not in the models?
To err is human; to really foul things up requires a computer.
– William Edward ‘Bill’ Vaughan, April 1969.
.. written just before the population bomb / global cooling / global warming / climate change / whatever-it’s-called-now ideology took off by scaring people into thinking that that the world was coming to an end.
It’s also good to have a huge dollop of charisma in getting that “world is coming to an end” message across.
Honestly, the Climate Change academic crowd make Charismatic-Pentecostal, hell-fire-and-damnation preachers look like wall flowers at a high school dance.
That Figure 1 is actually rather interesting it shows inter alii
Climate models can’t handle upwelling
Climate models can’t handle water/sea ice interaction
Climate models can’t handle the Antarctic convergence
“Although the human impact of recent climate change is now clear” So how is the impact from “recent” climate change clear? The only clarity I see is no impact. Normal ups and downs of temperatures, storms, etc. These people make this claim without a bit of evidence. They assume we are all aware of numerous articles or reports that offer vague, uncollaborated evidence of fossil fuel induced climate “extremes” and act as if those documents demonstrate it “is now clear”.