Consensus on Ecological Impacts Remains Elusive

CLIMATE CHANGEWhen Working Group II, part of the Intergovernmental Panel on Climate Change, reviewed 44 studies showing that more than 400 species of plants and animals across the globe had shifted their ranges or changed behaviors such as the timing of egg laying, the biologists on the committee considered this a strong signal of climate-induced effects on a variety of biota. But the nonbiologists, mostly economists, were less confident of the results. Now two big new studies strengthen the case that global warming is causing biological effects, but critics say even the additional data fall short of proof.