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what if we were wrong…..Most of us will feel confident the Intergovernmental Panel on Climate Change’s clutch of recent reports has now delivered a globally dependable well researched path to carbon neutrality. After all its the product of thousands of the world’s scientific experts. Actually, its most likely not the case. There are a number of prominent scientists who are saying that as we career past 1.5 towards 2 degrees warming the IPCC’s modelling is flawed and not fit for purpose. These scientists are anything but lightweight. Indeed, they are led by two of the world’s most well know economists – Sir Nicholas Stern (former World Bank Governor and author of the 2006 landmark Stern Review on the economics of climate change) and the Nobel laureate Joseph Stiglitz. Nevertheless, their findings are something of a well kept secret outside of academia, given they are only briefly referenced in the serval thousand pages of the IPCC’s recently released third report. Specifically, they warn the IPCC’s key integrated models (IAMs or integrated assessment models) on which policy prescriptions are based, fundamentally underestimate the urgency with which we have to act. They are therefore unlikely to provide reliable policy advice for economies which will be forced into increasingly radical and systemic change.
BY Dr Jeremy Webb
Stern and Stiglitz focus on the fact that we are now rapidly approaching the point of time when we will be unable to avoid shooting to a 2 degrees or more warming level. The problem is that once we arrive the IPCC’s current modelling becomes fundamentally unsuited to its task and is liable give us wrong projections on which to base our economic policies. They point to studies which warn that if we don’t stay below 2 degrees and still rely heavily on the sort of price mechanism which the current modelling is based “the risks rise so high as to be intolerable” and the cost “rise so high as to be, for all practical purposes infeasible”. The problem with 2 degrees and beyond, they argue, is that the IPCC’s integrated modelling is not well suited to this world of deep uncertainty, extreme risk and in which a raft of new issues arise. Here, Stern and Stiglitz point out, the economic and social damage from climate change can be immense with large irreversibilities and complex feedback effects giving rise to tipping points Stern and Stiglitz are not suggesting we throw out the current conventional modelling – which still, with a superhuman effort, could deliver a global temperature of below 1.5 degrees. However, if we reach a 2 degree plus world, relying on a carbon price to do the heavy lifting will be inadequate. In coming to this conclusion their reasoning involves at times some complex economics so this description is heavily simplified and does not cover the whole territory they traverse. They argue a far wider range of policies will be needed to guide countries towards effective climate targets involving the prospect of radical structural change and therefore new forms of growth and development. In other words, our current trajectory towards a 2 degree plus increase means we will face an economically and socially daunting level of radical and profound structural adjustments to our economy. Here the economy is most unlikely to follow conventional economic theory in which, after an external shock, it returns to a pre-existing equilibrium. All this generates a level of extreme social and economic disruption in which people’s preferences can fundamentally change and multiple simultaneous market failures are in prospect As well, as the timeframe extends and the extent of change becomes evident, major intergenerational equity issues arise. That is, the rising cost to and this distribution among the next generation becomes a major issue as is how we model it. Stern and Stiglitz draw attention to a number of individual studies which explore the radical disruption of a 2 degree plus world. However, their concern is that these studies when integrated into composite models produce very high levels of variability from very small changes in the variables. As such they become unreliable policy guides for governments. Feeding into Stern and Stiglitz’s concerns are the IPCC’s own risk assessments. Its most recent report doesn’t pull punches on where the globe is heading. It is, it states, ‘now almost inevitable’ that we will exceed 1.5 degrees based on current trends and in which case we will have to grapple with an era of irreversibility of effects. Indeed, the IPCC indicates we are currently on track to achieve a 1.5 degree increase in temperatures in the 2030s. To prevent going beyond into the unchartered waters of 2 degrees, GHG emissions must peak by 2025 and be almost halved within the decade. There are distressingly few indications we are willing to do what is needed to achieve this. Current national commitments will not deliver a limit of 1.5 degrees. No surprise here given Australia and other major gas, oil and coal producing countries are busy further expanding production – a direct rejection of the International Energy Agency’s carefully researched conclusion that there is already adequate global carbon capacity. Equally of concern is the IPCC’s modelling which gives such a major role to bio-sequestration and its reliance on withdrawing CO2 from the atmosphere. But this is precisely the area least policed and yet to be better researched. An EU study found that 85% of the UN sponsored carbon offset schemes did not actually reduce emissions in 2017. In Australia, studies indicate outright fraud in our carbon credit scheme which rely on bio-sequestration. Stern and Stiglitz – two of the world’s most respected economists – are thus offering Australia an urgent warning about the extraordinary risks in our headlong rush to a gas led recovery and a 2 degrees plus warming world.
READ MORE: https://johnmenadue.com/stern-and-stiglitz-the-chaotic-world-of-2-degrees-warming/
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too hot, too cold…..
BY PAUL VOOSEN
One study suggests Arctic rainfall will become dominant in the 2060s, decades earlier than expected. Another claims air pollution from forest fires in the western United States could triple by 2100. A third says a mass ocean extinction could arrive in just a few centuries.
All three studies, published in the past year, rely on projections of the future produced by some of the world’s next-generation climate models. But even the modelmakers acknowledge that many of these models have a glaring problem: predicting a future that gets too hot too fast. Although modelmakers are adapting to this reality, researchers who use the model projections to gauge the impacts of climate change have yet to follow suit. That has resulted in a parade of “faster than expected” results that threatens to undermine the credibility of climate science, some researchers fear.
Scientists need to get much choosier in how they use model results, a group of climate scientists argues in a commentary published today in Nature. Researchers should no longer simply use the average of all the climate model projections, which can result in global temperatures by 2100 up to 0.7°C warmer than an estimate from the Intergovernmental Panel on Climate Change (IPCC). “We need to use a slightly different approach,” says Zeke Hausfather, climate research lead at payment services company Stripe and lead author of the commentary. “We must move away from the naïve idea of model democracy.” Instead, he and his colleagues call for a model meritocracy, prioritizing, at times, results from models known to have more realistic warming rates.
Overall, climate models remain incredibly successful research tools, and nothing about this “too hot” generation invalidates the tenets of climate science, says Kate Marvel, a climate scientist at NASA’s Goddard Institute for Space Studies and co-author of the commentary. The greenhouse effect is still warming the planet. Ice is melting, seas are rising, and droughts are becoming more frequent in some areas. But the models are not perfect, Marvel says. “They’re not crystal balls.”
The problem of the too-hot models arose in 2019 from the Coupled Model Intercomparison Project (CMIP), which combines the results of the world’s models in advance of the major IPCC reports that come out every 7 or 8 years. In previous rounds of CMIP, most models projected a “climate sensitivity”—the warming expected when atmospheric carbon dioxide is doubled over preindustrial times—of between 2°C and 4.5°C. But for the 2019 CMIP6 round, 10 out of 55 of the models had sensitivities higher than 5°C—a stark departure. The results were also at odds with a landmark study that eschewed global modeling results and instead relied on paleoclimate and observational records to identify Earth’s climate sensitivity. It found that the value sits somewhere between 2.6°C and 3.9°C. The divergence in sensitivity estimates is a “sobering example of the complexity of the climate system,” says Christopher Field, a Stanford University climate scientist who focuses on impacts.
Researchers have since tracked down the causes of the too-hot models, which include those produced by the National Center for Atmospheric Research, the U.S. Department of Energy, the United Kingdom’s Met Office, and Environment and Climate Change Canada. They often relate to the way models render clouds; one result has been excessive predicted warming in the tropics.
A version of this story appeared in Science, Vol 376, Issue 6594.
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As we all know (we all should) global warming is likely to have more severe impact on some regions. Do we prepare for the worse or do we let Lismore be flooded again...? Yes, I know it's impossible to say that this or that is due to global warming because we, little middle of the road bourgeois, still live comfortably.... apart from the poor bastards who have lost everything.... or are starving (we blame the Ruskies for this) .... or have been insulted by Peter Dutton as the water from the sea lifts their floorboards.....
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