Craig Loehle

Craig Loehle is an American ecologist, a principal scientist at the National Council for Air and Stream Improvement, a forest industry-funded research institution and is listed as a policy expert for The Heartland Institute, a think tank famous for sponsoring climate change denial.
Scientific career
Loehle worked as a research ecologist at Savannah River Laboratory from 1987 to 1991, and in the environmental research division at Argonne National Laboratory from 1991 to 1998. While at Argonne, he conducted research which found that trees can grow to maturity up to a thousand miles south of their natural ranges, but only fifty to a hundred miles north of their natural ranges.
Scientific discovery and success
In 1990, in a paper in the journal BioScience, Loehle coined the term "Medawar zone" to refer to a scientific task which is only moderately difficult but still yields the maximum payoff. He named it after Peter Medawar, a Nobel Prize-winning scientist who once wrote that there seems to be a certain time when scientific questions seem especially ripe for answering, whereas other questions remain elusive and out-of-reach from investigation.
Climate change research
Loehle produced a paleoclimate reconstruction of temperatures over the last 2,000 years which avoided tree ring records on the basis that these were flawed, and used 18 series from a variety of other climate proxies. It was published on 1 December 2007 in Energy & Environment, a journal with a reputation for publishing papers promoting climate change denial. It became part of the hockey stick controversy as, unlike all other reconstructions, it showed Medieval Warm Period (MWP) temperatures warmer than current levels. Climatologists promptly highlighted various problems which should have been identified in peer review, including the mistaken assumption that the climate proxies were in years before 2000 when the scientific convention is that Before Present is years before 1950. The paper had shown the "MWP being approximately 0.3°C warmer than 20th century values at these eighteen sites", The corrected reconstruction as featured in the IPCC Fifth Assessment Report was assessed as showing it likely that the warmest tridecade in the MWP was colder than the 1983-2012 mean instrumental temperature.
A 2009 paper by Loehle reported that the global oceans had been cooling since 2003.
A 2014 study by him concluded that climate sensitivity was 1.99 °C, with a 95% confidence limit of 1.75-2.23 °C.

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