A recent study published in Science predicts there will be no comfort for US southerners in the future. As reported in the Atlantic
The American South Will Bear the Worst of Climate Change’s Costs
Global warming will intensify regional inequality in the United States, according to a revolutionary new economic assessment of the phenomenon.
The study, published Thursday in Science, simulates the costs of global warming in excruciating detail, modeling every day of weather in every U.S. county during the 21st century. It finds enormous disparities in how rising temperatures will affect American communities: Texas, Florida, and the Deep South will bleed income in the broiling heat, while some chillier northern states gain moderate benefits.
“We are really sure the South is going to get hammered,” says Solomon Hsiang, one of the authors of the paper and a professor of public policy at the University of California, Berkeley. “The South is really, really negatively affected by climate change, much more so than the North. That wasn’t something we were expecting going in.”
First of all, this comes from model projections, not from observed temperatures and precipitation.
The graph shows daily maximums, averaged annually for the southern region as defined by the National Weather Service (NWS). The rise since 1895 is less than 1F, not even noticeable. You can also clearly see a quasi-60 year cycle, and that we are coming off the warmer phase with a cooler phase likely ahead.
Precipitation over the same period of 120 years shows a slight rise, nothing dramatic, and also oscillating with scattered peaks and valleys.
Secondly, all forecasting was done using the worst-case scenario
Out of five scenarios in IPCC report RCP8.5 is the most extreme. Neither AR5 nor the paper describing RCP8.5 call it a “business as usual” scenario, because it is not. Such a scenario would assume continuation of existing trends through 2100. A worst-case scenario assumes trends change for the worse. RCP8.5 assumes population growth at the 90th percentile of the probability forecast for 2100 (i.e., not considering real-world factors) and near-stagnation of technological progress.
Thirdly the models show no skill at all at regional forecasting, never mind their deficiencies at the global scale.
Roger Pielke Sr. repeatedly points to the elephant in the room about these papers — the ignored assumption that climate models’ predictions about global climate (when fed accurate predictions about emissions) are a sufficiently skillful basis for public policy — and that downscaling these models produces regional forecasts also useful for making public policy. There is little evidence of either. See here for a discussion of the literature about model validation (see the end section here for links to the literature). He says there is even less evidence for their skill at regional levels. He reviewed the literature validating regional downsizing five years ago, and relatively little progress has been made since then.
From Larry Kummer, US Economic Damage from Climate Change
Finally, and perhaps most importantly, Adaptation by humans is not allowed.
The projections presume that humans will not adapt in response to changing conditions, even though we have always done so, and presently have unprecedented capacities.
Matthew Kahn explains this clearly in Climate Change Adaptation Economics
An econometric research team follows the following recipe. First, it takes historical data and estimates how weather conditions correlate with economic conditions. For example, when it is extremely hot in a county — do we observe based on past data that the county’s per-capita income is lower than usual. The research team takes these past correlations and takes a climate change model (that tells you a guess of what will be future climate conditions by county) to predict future economic outcomes under the assumption that the historical correlation between weather and economic outcomes persists into the future.
This bold writing violates the Lucas Critique. Robert Lucas is one of the University of Chicago’s greatest economists. I was not one of his greatest students but I learned from him that as the “Rules of the Game” change that forward looking decision makers re-optimize. He studied this issue in the context of government counter-cyclical macro policy (i.e tax cuts during recessions) but the same point applies in the case of climate change. (my bold)
Let me explain;
Suppose it has always been 90 degrees in Phoenix in April but moving forward it will now be 105 degrees on average in Phoenix in April because of climate change. This is what I mean by a change in the Rules of the Game. The key stochastic process’ core parameters have changed. The climate scientists estimate such relationship using geocoded time series data. They spread their findings (through the New York Times and through wild bloggers such as Joe Romm).
Investors (those who invest in durable buildings, businesses, families) who live and work in a specific area such as Phoenix have strong incentives to take pro-active actions to reduce their exposure to hotter Aprils. They have thousands of adaptation strategies (and richer people have even more). One of the points I argue in Climatopolis is that induced innovation will take place because of Paul Revere style forecasts of hotter summers. Demand creates supply! I haven’t even mentioned government at the local, state or federal level. While many adaptation strategies are private goods (think of air conditioners), there are also public goods (sea walls, air cooling centers). If government changes its investments because of the new “Rules of the Game”, then the poor’s well being can improve in the face of a changing climate even if they can’t afford any of the private adaptation strategies. We are not passive victims here. The greatness of capitalism is that the set of alternatives we have to choose from keeps growing due to innovation and product differentiation. Each of these private and public goods helps us to individually and collective adapt.
As these changes takes place, the historical correlations between climate and economic losses are attenuated. This is why I don’t have much confidence in the predictions reported in the new Science Paper.
Alarmist blinders could not be more obvious. Their only solution is spending many trillions of dollars attempting to prevent future warming and climate change by reducing CO2 emissions (so-called “Mitigation”). The much more rational and time-honored policy of Adaptation would mean watching for changes and challenges to actually appear then mobilizing resources in response. But that would mean waiting because nothing is yet happening outside the normal range of temperatures and precipitation. Unacceptable to true believers.
See also Climate Gloom and Doom