Climate Change: Expertise vs. Doubt

RE JEFF Jacoby's Dec. 24 op-ed "Climate of fear": The reality is that the science of climate change is complicated. Understanding what is happening requires linking data and insights from meteorology, geochemistry, oceanography, biology, and Earth history, among other disciplines. In this situation, pronouncements by laypeople that contradict the considered judgment of expert groups should not be taken seriously.

The Earth is now warming rapidly compared to what is expected from the long record of natural climatic changes. The main causes of this exceptional warming are human activities — the combustion of fossil fuels and tropical deforestation. The disruption of climatic patterns associated with the warming is endangering the productivity of farms, forests, and fisheries; coastal property; public health; and the biodiversity of the planet. Those are the conclusions of the US National Academy of Sciences, the American Geophysical Union, the Intergovernmental Panel on Climate Change, and many other national and international bodies that together have drawn on the expertise of thousands of scientists in the relevant disciplines.

If, as Jacoby writes, only 36 percent of the American public "worry a great deal" about climate change, much of the responsibility for that lamentable lag in understanding surely lies with the sort of uninformed wishful thinking that he is propagating.

JOHN P. HOLDREN
Falmouth
The author is director of the Woods Hole Research Center and a professor of environmental science and policy at Harvard.