Report: There is a 99.999% Certainty That Humans Driving Global Warming

earth-screensaver_largeThere is a new report on global climate change this week that addresses many of the claims being raised against the theory by critics. Despite the overwhelming agreement of the scientific community, people continue to cite anecdotal observations of cool temperatures to refute predictions. The new report crunches the climate numbers and concludes that there is less than 1 chance in 100,000 that global average temperature over the past 60 years would have been as high without human-caused greenhouse gas emissions.

The research published in Climate Risk Management by Philip Kokica, Steven Crimpc, and Mark Howdend is reportedly the first to quantify the probability of historical changes in global temperatures. They directly address the arguments promulgated by climate change critics:

December 2013 was the 346th consecutive month where global land and ocean average surface temperature exceeded the 20th century monthly average, with February 1985 the last time mean temperature fell below this value. Even given these and other extraordinary statistics, public acceptance of human induced climate change and confidence in the supporting science has declined since 2007. The degree of uncertainty as to whether observed climate changes are due to human activity or are part of natural systems fluctuations remains a major stumbling block to effective adaptation action and risk management. Previous approaches to attribute change include qualitative expert-assessment approaches such as used in IPCC reports and use of ‘fingerprinting’ methods based on global climate models. Here we develop an alternative approach which provides a rigorous probabilistic statistical assessment of the link between observed climate changes and human activities in a way that can inform formal climate risk assessment. We construct and validate a time series model of anomalous global temperatures to June 2010, using rates of greenhouse gas (GHG) emissions, as well as other causal factors including solar radiation, volcanic forcing and the El Niño Southern Oscillation. When the effect of GHGs is removed, bootstrap simulation of the model reveals that there is less than a one in one hundred thousand chance of observing an unbroken sequence of 304 months (our analysis extends to June 2010) with mean surface temperature exceeding the 20th century average. We also show that one would expect a far greater number of short periods of falling global temperatures (as observed since 1998) if climate change was not occurring. This approach to assessing probabilities of human influence on global temperature could be transferred to other climate variables and extremes allowing enhanced formal risk assessment of climate change.

They note that July 2014 was the 353rd consecutive month in which global land and ocean average surface temperature exceeded the 20th-century monthly average. Notably, anyone born after February 1985 has not lived a single month where the global temperature was below the long-term average for that month. Their analysis put the probability of getting the same run of “warmer-than-average months without the human influence was less than 1 chance in 100,000.”

We identified periods of declining temperature by using a moving 10-year window (1950 to 1959, 1951 to 1960, 1952 to 1961, etc.) through the entire 60-year record. We identified 11 such short time periods where global temperatures declined.

Our analysis showed that in the absence of human-caused greenhouse gas emissions, there would have been more than twice as many periods of short-term cooling than are found in the observed data.

It is an interesting paper that I recommend to you. I am obviously already sold on the concept of climate change and strongly disagree with those fighting efforts to control the pollution linked to the change. However, we can have a civil discourse on the subject and I believe that this is a credible report worthy of inclusion in that ongoing debate.

363 thoughts on “Report: There is a 99.999% Certainty That Humans Driving Global Warming”

  1. Genuinely no matter if someone doesn’t know after that its up
    to other visitors that they will assist, so here it happens.

  2. The models do not account for Earth’s wobbly and elliptical orbit around the Sun (and are missing other covariate data) and thus any results derived from the models are suspect. As are any claims of 99.999% certainty.

    Playing with Numbers

    Global climate and temperature cycles are the result of a complex interplay between a variety of causes. Because these cycles and events overlap, sometimes compounding one another, sometimes canceling one another out, it is inaccurate to imply a statistically significant trend in climate or temperature patterns from just a few years or a few decades of data.

    Unfortunately, a lot of disinformation about where Earth’s climate is heading is being propagated by “scientists” who use improper statistical methods, short-term temperature trends, or faulty computer models to make analytical and anecdotal projections about the significance of man-made influences to Earth’s climate.

    During the last 100 years there have been two general cycles of warming and cooling recorded in the U.S. We are currently in the second warming cycle. Overall, U.S. temperatures show no significant warming trend over the last 100 years (1). This has been well – established but not well – publicized.

  3. Darren: Yes, it’s the same one or in the same vicinity of an eruption that caused Ben Franklin to speculate on the nature of climates.

  4. Karen, You are doing well avoiding the darkness and following the light and positive. I bet you feel better.

  5. Rainparade:

    I haven’t been following this volcano’s news closely but I am aware of it. I didn’t know it could be that dire. But, having been through the Mt. St. Helen’s eruption in ’80 I know the effects to some degree. 🙂

  6. Jim22: RE: The politicization of fracking. And your point is?

    My point is that when enterprises destroy the commons, people turn to government for redress. It does no good to sue for damages when your water supply has been poisoned. And Dick Cheney was the one perverted the politics of fracking for his own profit. I thought that would have been obvious, even to you.

    And then to bring Yoko Ono into the conversation is a non-sequitur on par with Schulte bleating about Dr. Mann.

    Apparently your point is on the top of your head.

  7. Annie: Right on about Karen. It’s remarkable how that “open mind” always seem to see the logic of the neocon; which is no logic at all, unless you happen to be an offshore tax-havening POS

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