Study: Extreme Decadal Wind Variability Adds Uncertainty to Climate Predictions

Guest essay by Eric Worrall

My question – how can renewable energy possibly be a viable option, if we are entering a period of violent weather extremes, including wind droughts which could last for a decade?

Missing wind variability means future impacts of climate change may be underestimated in Europe and North America

by  University of Reading

Extratropical winds have a strong influence on climate in extratropical regions, and are known to vary from decade to decade. However, their variability is currently not factored into climate models making predictions for future climates in these regions. Researchers inserted these into predictions for how extratropical climates will change by the middle of the century, and found uncertainty increased significantly, meaning unusually hot, cold, dry or wet decades are likely to be more frequent here than previously thought.

Scientists at the University of Reading have warned that current projections of how a warming world will affect regional temperatures and rainfall do not take into account the fact that extratropical winds—which have a strong influence on climate in the mid-latitudes—vary greatly from decade to decade.

Dr. Christopher O’Reilly, a Royal Society University Research Fellow in the University of Reading’s Department of Meteorology, said: “Variations between decades in the strength of winds in the more temperate regions of the world are a crucial missing ingredient in projections of the future climate of those regions.

“By adding this extra variability into climate models, we showed that these winds may be an additional source of uncertainty on top of climate change. This could mean that within these regions, temperatures are pushed to relatively extreme highs or lows more often. While in some decades they could counteract increases to temperatures and heavy rainfall caused by climate change, in other periods they could make these extremes even more extreme.

Read more: https://phys.org/news/2021-09-variability-future-impacts-climate-underestimated.html

The abstract of the study;

Projections of northern hemisphere extratropical climate underestimate internal variability and associated uncertainty

Christopher H. O’ReillyDaniel J. BefortAntje WeisheimerTim WoollingsAndrew Ballinger & Gabriele Hegerl 

Abstract

Internal climate variability will play a major role in determining change on regional scales under global warming. In the extratropics, large-scale atmospheric circulation is responsible for much of observed regional climate variability, from seasonal to multidecadal timescales. However, the extratropical circulation variability on multidecadal timescales is systematically weaker in coupled climate models. Here we show that projections of future extratropical climate from coupled model simulations significantly underestimate the projected uncertainty range originating from large-scale atmospheric circulation variability. Using observational datasets and large ensembles of coupled climate models, we produce synthetic ensemble projections constrained to have variability consistent with the large-scale atmospheric circulation in observations. Compared to the raw model projections, the synthetic observationally-constrained projections exhibit an increased uncertainty in projected 21st century temperature and precipitation changes across much of the Northern extratropics. This increased uncertainty is also associated with an increase of the projected occurrence of future extreme seasons.

Read more: https://www.nature.com/articles/s43247-021-00268-7

Delving into the study, they seem to be suggesting adding observed wind variability to model projections increases the likelihood of harsh winters, rainfall anomalies and extreme heatwaves, and leads to a significant underestimate of internal variability in existing climate models.

For future twenty-first century periods, the underestimation of the uncertainty due to large-scale atmospheric circulation is comparable with the structural uncertainty in the forced response55,56. An example of where this underestimation could be important is the recent literature considering the differing impacts of 1.5 and 2 °C of global warming57; the underestimation of internal variability in the extratropics implies that regional differences between 1.5 and 2 °C warming are likely to be somewhat overconfident. Furthermore, the increased uncertainty also raises questions about the treatment of internal variability in regional model projections58. The EURO-CORDEX ensemble59, for example, use a relatively small subset of global coupled climate model simulations that, as has shown here, themselves underestimate the contribution of internal variability and this will be compounded in projections made using regional model ensembles. The increased projection uncertainty may also be important to factor into future risk assessment and decision making exercises.

Read more: Same link as above

The thrust of the study seems to be an attempt to amplify alarm about 1.5C warming – if some of the effects projected to occur with 2C of global warming start leaking through to a 1.5C world, you get an enhanced woo woo factor.

But a big issue the study authors avoided, what does all this claimed enhanced weather variability imply for the future of renewable energy?

Europe is currently suffering a severe wind drought, which has cause power price spikes and factory shutdowns across the continent.

Imagine the current European wind drought extending until 2030. Or Northern Hemisphere solar installations rendered unusable by a series of unusually cloudy summers. Or a series of extreme wind and hail storms sweeping Europe, destroying vast swathes of fragile wind and solar infrastructure.

If you believe in climate models and accept the results of this study, the inescapable conclusion must be that any attempt to go 100% renewable would be an economic disaster. I mean we already knew that, but a prediction of even more extreme weather anomalies than models predict surely drives home the message that renewable energy is not a viable solution to the world’s energy needs.

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September 20, 2021 at 08:35PM

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