john christy

Post image for Climate Models: “Epic Failure” or “Spot on Consistent” with Observed Warming?

NASA scientist Roy Spencer recently posted on his Web site some startling graphs produced by John Christy, his colleague at the University of Alabama in Huntsville. The graph immediately below compares the linear-trend temperature projections of 73 climate models with the linear trend of observed temperatures for the bulk tropical atmosphere during 1979-2012.


The 73 models are part of the fifth phase of the Coupled Model Intercomparison Project (CMIP-5), a collaborative effort of 20+ modeling groups to inform the IPCC’s forthcoming Fifth Assessment Report (AR5). The Project’s three main objectives are to “evaluate how realistic the models are in simulating the recent past,” “provide projections of future climate change” out to 2035 and 2100, and “understand some of the factors responsible for differences in model outputs” such as different estimates of feedback effects.

Christy’s graph reveals what Spencer calls an “epic failure” of the models to match the actual behavior of the tropical atmosphere. Models that overestimate recent warming are likely to overestimate future warming as well.

Of course, observational systems may have biases and errors, but that is an implausible explanation for the mismatch. The observations come from two satellite and four radiosonde (weather balloon) datasets, which all independently give “virtually identical trends.”

What about the subset of U.S.-designed models — do they get the trend right? Nope. Take a gander at the next graph.


[click to continue…]

Post image for John Christy: Climate Change Overview in Six Slides

Yesterday, Rep. David McKinley (R-W.Va.) hosted a climate change conference in a technology park in Fairmont, W.Va.

A mixed panel of warmistas and skeptics featured Marc Marano of Climate Depot, Scott Denning of Colorado State University, Jim Hurrell of the National Center for Atmospheric Research, Joe Casola of the Center for Climate and Energy Solutions, Annie Petsonk of Environmental Defense Fund, Myron Ebell of the Competitive Enterprise Institute, Dennis Avery of the Hudson Institute, and John Christy of the University of Alabama in Huntsville, who participated by satellite link.

I emailed Dr. Christy and asked for permission to post his presentation on GlobalWarming.Org; he promptly sent me the files.

Dr. Christy’s Power Point presentation is available here. The accompanying text is available here. The main takeaway points:

  • Popular scare stories that weather extremes — hurricanes, tornadoes, droughts, floods — are getting worse are not based on fact.
  • In the U.S., high temperature records are not becoming more numerous.
  • Climate models significantly overestimated warming during the past 15 years.
  • Even if climate models were correct, a 50% reduction in U.S. CO2 emissions by 2050 would avert only 0.07°C of warming by 2100.
  • If a policy is not economically sustainable, it’s not politically sustainable.
  • The climate change impact of enhancing CO2 concentrations has so far been small compared to the public health and biospheric benefits provided by affordable, carbon-based energy.
Post image for Sen. Whitehouse Fumes at ‘Climate Deniers’

In a fiery speech yesterday, Sen. Sheldon Whitehouse (D-R.I.) “calls out” “climate deniers.” In the first half of the speech he goes ad hominem, attacking opponents as “front groups” who take payola from “polluters” to “confuse” the public by selling “doubt” as their product.

First a bit of free advice for the good Senator:

Your team has been playing nasty from day one. It didn’t get you cap-and-trade, it didn’t get you Senate ratification of the Kyoto Protocol, and it’s not going to get you a carbon tax.  

Vilification doesn’t work because biomass, wind turbines, and solar panels are not up to the challenge of powering a modern economy, and most Americans are too practical to believe otherwise.

So by all means, keep talking trash about your opponents. The shriller your rhetoric, the more skeptical the public will become about your bona fides as an honest broker of “the science.”

Okay, let’s examine Sen. Whitehouse’s argument. He accuses skeptics of peddling “straw man arguments,” such as that “the earth’s climate always changes; it’s been warmer in the past.” Well, it does, and it has! Many studies indicate the Medieval Warm Period (MWP) was warmer than the current warm period (CWP). A study published in July in Nature Climate Change concludes the Roman Warm Period (RWP) was warmer than both the MWP and CWP. The Northern Hemisphere was substantially warmer than the present for thousands of years during the Holocene Climate Optimum (~5,000-9,000 years ago). Arctic summer air temperatures were 4-5°C above present temperatures for millennia during the previous interglacial period.

None of this is evidence man-made global warming is not occurring, but Sen. Whitehouse sets up his own straw man by making that the main issue in dispute. What the paleoclimate information does indicate is that the warmth of the past 50 years is not outside the range of natural variability and is no cause for alarm. The greater-than-present warmth of the Holocene Optimum, RWP, and MWP contributed to improvements in human health and welfare[click to continue…]

Post image for John Christy on Summer Heat and James Hansen’s PNAS Study

In a recent study published in Procedings of the National Academy of Sciences (PNAS), NASA scientist James Hansen and two colleagues find that whereas “extremely hot” summer weather “practically did not exist” during 1951-1980, such weather affected between 4% and 13% of the Northern Hemisphere land area during 2006-2011. The researchers infer that human-caused global warming is “loading” the “climate dice” towards extreme heat anomalies. They conclude with a “high degree of confidence” that the 2003 European heat wave, the 2010 Russian heat wave, and the 2011 Texas-Oklahoma drought were a “consequence of global warming” and have (as Hansen put it in a recent op-ed) “virtually no explanation other than climate change.”

In a recent post, I reviewed studies finding that the aforementioned anomalies were chiefly due to natural variability. In another post, I summarized an analysis by Patrick Michaels and Chip Knappenberger, who conclude that “the 2012 drought conditions, and every other [U.S.] drought that has come before, is the result of natural processes, not human greenhouse gas emissions.”

But what about the very hot weather afflicting much of the U.S. this summer? Greenhouse gas concentrations keep rising, heat spells are bound to become more frequent and severe as the world warms, and the National Oceanic and Atmospheric Administration (NOAA) reports that July 2012 was the hottest July ever in the U.S. instrumental record. Isn’t this summer what greenhouse warming “looks like“? What else could it be?

University of Alabama in Huntsville (UAH) climatologist John Christy addressed these questions last week in a two-part column. In Part 1, Christy argues that U.S. daily mean temperature (TMean) data, on which NOAA based its report, “do not represent the deep atmosphere where the enhanced greenhouse effect should be detected, so making claims about causes is unwise.” A better measure of the greenhouse effect is daily maximum temperature (TMax), and TMax records set in the 1930s remain unbroken. In Part 2, Christy argues that Hansen’s 10% estimate of the portion of land affected by extreme heat during 2006-2011 shrinks down to 2.9% when anomalies are measured against a longer, more representative climate baseline.  [click to continue…]

Post image for Hansen’s Study: Did Global Warming Cause Recent Extreme Weather Events?

A study by NASA’s James Hansen and two colleagues, published Monday in Proceedings of the National Academy of Sciences (PNAS), finds that during the past 30 years, extreme hot weather has become more frequent and affects a larger area of the world than was the case during the preceding 30 years. Specifically, the study, “Perception of climate change,” reports that:

  • Cool summers occurred one-third of the time during 1951-1980 but occurred only 10% of the time during 1981-2010.
  • Very hot weather affected 0.2% of the land area during 1951-1980 but affected 10% of the land area during 1981-2010.

Hansen is the world’s best known scientist in the climate alarm camp and a leading advocate of aggressive measures to curb fossil-energy use. He and his co-authors are up front about the policy agenda motivating their study. The “notorious variability of local weather and climate from day to day and year to year” is the “great barrier” to “public recognition” of man-made climate change and, thus, to public support for policies requiring “rapid reduction of fossil fuel emissions.” When heat waves or drought strike, the authors want the public to perceive global warming. On Saturday, the Washington Post published an op-ed by Hansen summarizing the study’s results.

Heat waves will become more frequent and severe as the world warms; some areas will become drier, others wetter. Those hypotheses are not controversial.

What the Hansen team concludes, however, is controversial. The researchers contend that the biggest, baddest hot weather extremes of recent years — the 2003 European heat wave, the 2010 Russian heat wave, the 2011 Texas-Oklahoma drought, the ongoing Midwest drought — are a “consequence of global warming” and have “virtually no explanation other than climate change.”

There’s just one small problem. The reseachers do not examine any of those events to assess the relative contributions of natural climate variability and global warming. The study provides no event-specific evidence that the record-setting heat waves or droughts would not have occurred in the absence of warming, or would not have broken records in the absence of warming.  [click to continue…]

Post image for John Christy: Climate Data Maven

Earlier this week, the Senate Environment & Public Works Committee held a hearing entitled “Update on the Latest Climate Change Science and Adaptation Measures.” Testimony by Dr. John Christy of the University of Alabama Huntsville is too valuable not to share with the millions (okay, hundreds) of folks who visit this site.

Christy is a data maven. He spends “tedious” weeks and months examining surface observations as well as weather balloon and satellite measurements to build “datasets from scratch to advance our understanding of what the climate is doing and why.” He uses the datasets “to test hypotheses of climate variability and change.” Yes, it’s called the scientific method, but much of what passes for climate science today is, in Christy’s words, “opinion, arguments from authority, dramatic press releases, and fuzzy notions of consensus generated by a preselected group.”

Increasingly, we hear experts blame global warming for bad weather. Most acknowledge that no single weather event can be attributed to global climate change. However, they contend, the pattern of recent events — the sheer number and severity of heat waves, wild fires, droughts, freak storms — is exactly what climate scientists have predicted and must be due to mankind’s fuelish ways. Such assertions, Christy shows, are not based on real data. [click to continue…]

Last Thursday, the House Energy & Power Subcommittee, on a voice vote, approved H.R. 910, the “Energy Tax Prevention Act.” My colleague Myron Ebell blogged about it over the weekend in a post titled Inside the Beltway.

The present post offers additional commentary. The full House Energy and Commerce Committee marks up the legislation today and tomorrow.

Rep. Henry Waxman (D-Calif.) led the charge for the minority, claiming H.R. 910 “rolls back” the Clean Air Act. Wrong. H.R. 910 restores the Clean Air Act (CAA). Congress never intended the CAA to be a framework for greenhouse gas regulation, and never subsequently voted for it to be used as such a framework. The terms “greenhouse gas” and “greenhouse effect” never even occur in the Act, which was enacted in 1970, years before global warming was even a gleam in Al Gore’s eye.  [click to continue…]

Last week’s House Ways & Means Committee hearing on “scientific objectives for climate change legislation” contained much grist for skeptical mills.

Dr. James Hansen did not challenge any of Dr. John Christy’s specific arguments that UN climate models overestimate climate sensitivity. Instead, he advised Congress to ask the National Academy of Sciences for an “authoritative” assessment, because the science is “crystal clear.”

Hansen was quite harsh in criticizing Kyoto (an “abject failure”) and carbon trading (a politically unsustainable hidden tax for the benefit of special interests). He outlined a proposal for what he calls carbon “Tax & Dividend,” whereby 100% of the revenues would be refunded to the American people via monthly deposits to their bank accounts.

As I discuss here, Hansen’s beguiling proposal could decimate coal-based power in a decade or two, pushing electricity prices up faster than dividend payments increase, and saddling the economy with a growth-chilling energy crisis.