Professors react to flawed climate lecture

Authors:

Dr. Benjamin W. Johnson, Earth, atmosphere and climate (EAC)

Dr. Jacqueline Reber, EAC

Dr. Alan Wanamaker, EAC

Dr. Lindsay C. Maudlin, EAC

Dr. William Gutowski, EAC

Dr. Lee Anne Willson, physics and astronomy

Dr. Clark Wolf, philosophy and political science

Dr. Diana Thatcher, EAC

Dr. Elizabeth Swanner, EAC

Dr. Cinzia Cervato, EAC

We are a group of faculty from the departments of Earth, atmosphere and climate, physics and astronomy, sustainable agriculture, philosophy and political science. We are writing in reply to a recent public lecture titled “A Fresh Look at Anthropogenic Climate Change” by Dr. David Legates, which took place on April 29.

In his presentation, Dr. Legates argued that anthropogenic climate change is not a serious concern and that we should not, therefore, consider the implementation of policies designed to reduce greenhouse gas emissions. 

As researchers who study climate science and climate policy, with decades of research experience in climate, paleoclimate, stellar and planetary atmospheres, Earth science and public policy, we found this presentation seriously misrepresented both the science and the need for public policy to address climate change. 

It is a common approach among climate denialists to imply controversy about issues that are in fact the object of a strong consensus among qualified researchers who work in this area. Such a “manufactroversy” highlights uncertainties in data or models, and wrongly suggests that they constitute evidence that these data and models are untrustworthy.

The scientific consensus, echoed by professional organizations including the American Geophysical Union, the Geological Society of America and the American Meteorological Society, concretely states that human activity has increased carbon dioxide (CO₂) and other greenhouse gases in the atmosphere, this increase drives warming of the atmosphere and oceans, and climate change “is proving increasingly costly and disruptive worldwide.”

Dr. Legates’ lecture did not present a balanced, scientifically rigorous account of climate research. Instead, he delivered an agenda-driven set of non-representative data. In this note, we will highlight some key themes and examples of this misleading presentation.

There were three overarching problems with Dr. Legates’ presentation: First, Dr. Legates claimed that many observed trends, including increases in temperature, precipitation and extreme events (droughts, floods) are simply the result of changing measurement methods. Second, his depiction of the effects of greenhouse gases on climate and ecosystems misrepresented fundamental science. Third and finally, he presented non-representative data that obscured clear trends.

1) Measurement methods and data collection 

Dr. Legates repeatedly claimed that the locations of weather stations or specific instruments used to measure temperature, precipitation and other climate variables are responsible for trends indicating anthropogenic climate change.

He suggested that data on rainfall collected before the mid-1990s were untrustworthy because of the effects of evaporation and wind, and that the clear increase in precipitation (caused by a warming climate) was due to the installation of new rain gauges. Such a claim reveals ignorance of how science and scientists collect and record data. 

Scientific research requires scrupulous care in data collection, and scientists are careful to control for changes in instrumentation, including the influence of evaporation and wind, that might influence results. Legates’s implication that data collection methods are sloppy and unreliable reveals a fundamental misunderstanding of scientific methods.

2) Misrepresentation of fundamental science: 

Dr. Legates presented a flawed understanding of the climate, how we study climate and the links between agriculture and climate. He suggested that climate models that predict future climate response to warming “only show the worst-case scenario.” But this is false. Climate modeling studies routinely include a variety of different potential CO₂ emissions scenarios and project a wide range of expected outcomes. 

Contrary to Dr. Legates’ claim, the average of all projections included in the most recent report from the Intergovernmental Panel on Climate Change (IPCC) has quite accurately tracked the rate of measured warming over the period 1970-2020. 

Nitrous oxide (N₂O) is released from many industrial and agricultural activities. Dr. Legates claimed that nitrous oxide is present at such low abundance that it does not influence warming. Again, this is false and misleading. Dr. Legates suggested that proposed climate policies would undermine agricultural productivity, sacrificing human interests for the sake of environmental preservation. 

But this is a false choice: there are many creative solutions that would maintain agricultural production while mitigating excess nitrogen. A sensible climate policy need not sacrifice human interests for the sake of environmental protection.

3) Non-representative data: 

The data shown in this talk focused on local and short duration, which do not represent the spatial and time scales over which climate change occurs. He included no paleoclimate data, which stretches back many thousands to millions of years. Inclusion of such data reveals that the timing and tempo of anthropogenic climate change differ from natural underlying climate fluctuations. 

Dr. Legates predominantly cited data from the continental U.S. and did not reveal the baseline to which he was comparing data. This is misleading because it obscures and smears out regional variability. His omission of widely available global datasets led to a systematically misleading presentation of global climate change data.

One additional, serious reservation about Dr. Legates’ presentation concerns not the presentation of data, but unrevealed conflicts of interest. Dr. Legates has been associated with the Heartland Institute and is currently associated with the Independent Institute. 

Both organizations reject the scientific consensus on climate change and promote climate change denial. Both organizations suggest that climate change is not an urgent problem and, therefore, does not require action. 

The Heartland Institute has received funding from the oil and gas industry, while the Independent Institute has received funding from the Koch Foundation. Both funding sources have a financial interest in avoiding regulatory policies and in downplaying the influence of humans and fossil fuels on climate change.

We encourage interested readers of the Daily to look into climate-related courses, majors and research expertise here at Iowa State and beyond to develop an informed, scientifically validated understanding of climate change and its causes.

“So nature does indeed need protection from man, but man, too, needs protection from his own acts, for he is part of the living world. His war against nature is inevitably a war against himself. His heedless and destructive acts enter into the vast cycles of the earth, and in time return to him.”  — Rachel Carson