David Legates

Scientific work

Legates started his career working on precipitation probability modeling. He extended his research to the study of global precipitation and temperature measurement correlation and performed critical analyses of the quality of traditional water budgeting methods applied to recent, better quality measurement data. He also became concerned with the study of the applicability of global circulation prognostication models at the regional and local level. Legates and his team argued for the necessity of technological progress in precipitation measurement used for validating climate change scenarios, and for validation of existing data used for that purpose. They demonstrated disagreement between satellite-based and in-situ precipitation measurements, and pointed out inconsistencies among satellite data processing algorithms. Legates argued for a better adequacy of observation-based climatologies compared to those compiled subjectively. His team concluded that uncorrected centered-pattern correlation statistics applied to the validation of general circulation prognostication models used to predict large-scale climate change may be inappropriate and may yield erroneous results. They proposed modified goodness of fit test methods more suitable for use in hydrologic and hydroclimate model validation. Legates and his coworkers became concerned with the quality of surface instrumental temperature data analysis, treatment and presentation of trends used in the communication of global warming research results.

He co-developed methods to correct biases in gauge-measured precipitation data for wind and temperature effects, with direct applicability in climate change, hydrology and environmental impact studies. His group observed that gauge undercatch was mostly caused by wind turbulence—especially for snow—and has a significant effect on the calculated Arctic water budget. They also studied the correlation between the observed variability in Western US snowpack accumulation and atmospheric circulation in historical measurement data and developed temperature-snowfall correlations based on first principles and observation in order to improve the global radiation balance estimation used in climate change predictions. Legates also developed a calibration method which validates NEXRAD radar precipitation data with gauge measurements to improve the accuracy of precipitation estimates.

Legates and his coworkers extended their research to the development of correlations between satellite crop imaging data and landscape change, crop type and its evolution, and their effects of global climate change. They have also tackled rainfed crop management, modeling and optimization. The group developed a hydrologic model based on meteorological, soil and vegetation measurement data. His groups has demonstrated poor quality of correlation between hydrological cycle data, global runoff and global warming. Legates and coauthors (among which were Willie Soon, Sallie Baliunas, Timothy F. Ball and others) authored a controversial (and non peer-reviewed) paper in the journal Ecological Complexity attempting to disprove an increase in Hudson Bay temperatures in the past 70 years, and cautioning about polar bear-human interaction as a likely cause for any observed decline in bear populations. In this paper the authors expressed doubts regarding the predictive quality of global warming models at the entire Arctic scale and any extrapolation of polar bear population trends.

Position on global climate change

Legates is a signer of the Oregon Petition, which stated: "There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate. Moreover, there is substantial scientific evidence that increases in atmospheric carbon dioxide produce many beneficial effects upon the natural plant and animal environments of the Earth".

In his testimony to the United States Senate Committee on Environment and Public Works regarding the Mann, Bradley and Hughes hockey stick controversy, Legates summed up his position as: "Where we differ with Dr. Mann and his colleagues is in their construction of the hemispheric averaged time-series, their assertion that the 1990s are the warmest decade of the last millennium, and that human influences appear to be the only significant factor on globally averaged air temperature."

In his lectures, Legates has acknowledged that humans have a direct impact on the environment. However he has disputed large scale climatological studies where he claims that researchers fail to incorporate sufficient data involving increased solar activity, water vapor as a greenhouse gas, data contamination through expansion of the urban heat island effect surrounding data collection points, and many other key variables in addition to the human chemical emissions that are the sole focus of many climatological studies.

In October 2009, Dr. Legates and 34 cosigners submitted a letter to the EPA outlining specific objections to the proposed endangerment rule.

Legates is a signatory of the Cornwall Alliance for the Stewardship of Creation's "An Evangelical Declaration on Global Warming".

The declaration states:

"We believe Earth and its ecosystems — created by God’s intelligent design and infinite power and sustained by His faithful providence — are robust, resilient, self-regulating, and self-correcting, admirably suited for human flourishing, and displaying His glory. Earth's climate system is no exception."

Aftermath: use of his title in public statements

In February 2007, Delaware governor Ruth Ann Minner wrote a letter to Legates stating "Your views on climate change, as I understand them, are not aligned with those of my administration,". The letter directed Legates to stop using his title as state climatologist of Delaware in his public statements related to climate change.

Recent statements

Legates was a co-author of a 2015 study published by the Chinese Science Bulletin that used a simple climate model predicting an overall trend of approximately 1.0 C warming for the 2000 to 2100 period, drawing upon the historical record of approximately 0.34 C warming from 1990 to 2014. The study's authors, a team made up of Legates with Dr. Willie Soon, Dr. William M. Briggs, and Lord Christopher Monckton, stated that they somewhat agreed with the IPCC’s ideas but found the organization's temperature predictions to be largely overstated. The study specifically asserted that warming "may be no more than one-third to one-half of IPCC’s current projections".

Other affiliations

According to the News Journal, "the Union of Concerned Scientists published a study listing Legates among several scientists it described as 'familiar spokespeople from ExxonMobil-funded organizations' that have regularly taken stands or sponsored reports questioning the science behind climate change warnings." Legates is a senior scientist of the Marshall Institute, a research fellow with the Independent Institute, and an adjunct scholar of the Competitive Enterprise Institute, all of which have received funding from ExxonMobil.