Category Archives: Prediction

2019 ENSO forecast

by Judith Curry and Jim Johnstone

CFAN’s 2019 ENSO forecast is for a transition away from El Niño conditions as the summer progresses. The forecast for Sept-Oct-Nov 2019 calls for 60% probability of ENSO neutral conditions, with 40% probability of weak El Niño conditions. – Forecast issued 3/25/19

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Why climate predictions are so difficult

by Judith Curry

An insightful interview with Bjorn Stevens.

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What’s the worst case? Emissions/concentration scenarios

by Judith Curry

Is the RCP8.5 scenario plausible?

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Nature Unbound X – The next glaciation

by Javier

Summary: The IPCC expresses virtual certainty that a glaciation is not possible for the next 50 Kyr if CO2levels remain above 300 ppm. It is the long interglacial hypothesis. Analysis of interglacials of the past 800 Kyr shows they depend on obliquity-linked summer energy, ice-volume, and eccentricity, and they end at glacial inception after ~ 6000 years of Neoglaciation-type temperature decline. The lag between orbital forcing and ice volume change indicates the orbital threshold for glacial inception is crossed thousands of years before glacial inception, and the Holocene went through that threshold long ago. In the absence of sufficient anthropogenic forcing glacial inception should take place in 1500-2500 years. The long interglacial hypothesis rests on the wrong astronomical parameter, high-equilibrium climate sensitivity to CO2, and uncertain model predictions of very long-tailed CO2decay. It is not possible to determine at present if a glacial inception will take place over the next millennia. The precautionary principle indicates we should prepare for that eventuality as it would constitute the worst catastrophe humankind has ever faced.

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The Hansen forecasts 30 years later

by Ross McKitrick and John Christy

Note: this is a revised version to correct the statement about CFCs and methane in Scenario B.

How accurate were James Hansen’s 1988 testimony and subsequent JGR article forecasts of global warming? According to a laudatory article by AP’s Seth Borenstein, they “pretty much” came true, with other scientists claiming their accuracy was “astounding” and “incredible.”  Pat Michaels and Ryan Maue in the Wall Street Journal, and Calvin Beisner in the Daily Caller, disputed this.

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Nature Unbound IX – 21st Century Climate Change

by Javier

A conservative outlook on 21st century climate change

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Beyond ENSO: new signals of seasonal to interannual predictability

by Judith Curry

My new talk on improving seasonal to interannual climate predictions.

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ENSO forecast for 2018

by Jim Johnstone and Judith Curry

Attempting to breach the ENSO springtime  ‘predictability barrier.’

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RS Workshop on Handling Uncertainty in Weather & Climate Prediction. Part I

by Judith Curry

Later this week, the Royal Society is hosting a Workshop on Handling Uncertainty in Weather and Climate Prediction, With Application to Health, Agronomy, Hydrology, Energy and Economics.

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Cool first, warm later

by Judith Curry

From an article in the New Scientist by Fred Pearce, written in Sept 2009:

One of the world’s top climate modellers said Thursday we could be about to enter one or even two decades during which temperatures cool.

“I am not one of the sceptics,” insisted Mojib Latif of the Leibniz Institute of Marine Sciences at Kiel University, Germany. “However, we have to ask the nasty questions ourselves or other people will do it.”

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The weatherman is not a moron

by Judith Curry

Why are weather forecasters succeeding when other predictors fail? It’s because long ago they came to accept the imperfections in their knowledge. – Nate Silver

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Trends, change points & hypotheses

by Judith Curry

Jonathan Leake asks in the Sunday Times: “Why has it warmed so much less than the IPCC predicted?

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Climate scenarios: 2015-2050

by Judith Curry

Nature is about to carry out a very interesting experiment

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Climate models as ink blots

by Judith Curry

From Roger Pielke Jr.:  A fundamental problem with climate science in the public realm, as conventionally practiced by the IPCC, is the essential ink blot nature of its presentation. By “ink blot” I mean that there is literally nothing that could occur in the real world that would allow those who are skeptical of scientific claims to revise their views due to unfolding experience. That is to say, anything that occurs with respect to the climate on planet earth is “consistent with” projections made by the climate science community. 

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Anticipating the Climate Black Swan

by Judith Curry

I just received the reviews on the manuscript I submitted to special issue of the journal Climatic Change, entitled “Reasoning About Climate Uncertainty.”  Overall, the review was pretty mild.  One comment from the editor was about my paragraph that mentioned “black swans.”

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A prediction market for climate outcomes

by Judith Curry

I am a strong believer that academic freedom is essential for scientific progress, and such freedom includes the right to be “wrong.”  In fact, scientists can often learn much from failed experiments and failed predictions.  However, for regulatory science and science for policy, should there be some premium on (and some reward for) actually being “right”?  How can we know what is “right” in the short term? Shi-Ling Hsu has a provocative new essay that advocates an entirely different path for evaluating climate science that draws upon an institution that is truly independent: markets.
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Dempster on climate prediction

by Judith Curry

I spotted this presentation by Arthur Dempster, Harvard statistician, in the Series on Mathematical and Statistical Approaches to Climate Modeling hosted by the Isaac Newton Institute for Mathematical Sciences.

Dempster is widely known as the co-originator of Dempster-Shafer Evidence Theory (see the Wikipedia for an overview).  Elements of evidence theory have been discussed on several previous threads (see Italian Flag, reasoning about floods).

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Foxes, Hedgehogs and Prediction

by Judith Curry

Robert Ellison sent me a link to a review of a book entitled “Future Babble:  Why Expert Predictions Fail and Why We Believe Them“, by Dan Gardner, which describes the research of UC Berkeley Professor Philip Tetlock.

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Chaos, ergodicity, and attractors

by Tomas Milanovic

This post has been triggered by the following comment from Eli Rabbett in the spatio-temporal chaos thread :

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Winter Weather

by Judith Curry

In Atlanta right now, we have about 2″ of snow, overlain by freezing rain, a classical “winter mix.”  The whole city is pretty much closed down (including Georgia Tech).  This is a fairly wimpy storm relative to what I used to encounter in Boulder or Chicago, but dealing with weather is relative to what you have adapted to.  Madhav Khandekar from India posts at Pielke Sr.:

For last two weeks or about most of north and central India are witnessing cold wintry weather; some places in Kashmir and the Himalayan foothills have low temperatures at -5C to -20C! This is cold for India, since most houses are not insulated, not heated (except some small room heaters in north India) . . .

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Scenarios: 2010-2040. Part III: Climate Shifts

by Judith Curry

Interpretation of statistical or dynamical predictions of future climate change needs to appropriately interpret the modes of natural internal climate variability, such as the Atlantic Multidecadal Oscillation (AMO), the North Atlantic Oscillation (NAO), the Pacific Decadal Oscillation (PDO) and the North Pacific Gyre Oscillation (NPGO).  This interpretation is needed in the context of forced climate change (e.g. solar, greenhouse gases).

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