Journal Article

Global metabolic impacts of recent climate warming

Huey, Raymond B., Dillon, Michael E., Wang, George

2010

Overview

Metabolic impacts of climate warming Organisms living at mid- to high latitudes in the Northern Hemisphere have been predicted to be potentially the most affected by climate warming, as that is where temperatures have risen most rapidly. But Michael Dillon and colleagues now turn the spotlight onto the prospects for ectotherms — 'cold blooded' animals that regulate their body temperatures by exchanging heat with their surroundings — living in the tropics. Temperature rise does not have a linear effect on an organism's biology, and estimated warming-induced changes in metabolic rate for tropical ectotherms are found to be larger than, or equivalent in magnitude to, those observed in temperate climates. This work may have profound implications both locally and globally, because the tropics are an important engine of primary productivity and contain a large proportion of the world's biodiversity. Temperature increase does not have a linear effect on an organism's biology. These authors use observed global temperature change to calculate the change in metabolic rate for ectotherms. Despite smaller temperature increases in the tropics, these areas, which contain the largest proportion of biodiversity, are likely to experience just as much change in metabolic rate. Documented shifts in geographical ranges 1 , 2 , seasonal phenology 3 , 4 , community interactions 5 , genetics 3 , 6 and extinctions 7 have been attributed to recent global warming 8 , 9 , 10 . Many such biotic shifts have been detected at mid- to high latitudes in the Northern Hemisphere 4 , 9 , 10 —a latitudinal pattern that is expected 4 , 8 , 10 , 11 because warming is fastest in these regions 8 . In contrast, shifts in tropical regions are expected to be less marked 4 , 8 , 10 , 11 because warming is less pronounced there 8 . However, biotic impacts of warming are mediated through physiology, and metabolic rate, which is a fundamental measure of physiological activity and ecological impact, increases exponentially rather than linearly with temperature in ectotherms 12 . Therefore, tropical ectotherms (with warm baseline temperatures) should experience larger absolute shifts in metabolic rate than the magnitude of tropical temperature change itself would suggest, but the impact of climate warming on metabolic rate has never been quantified on a global scale. Here we show that estimated changes in terrestrial metabolic rates in the tropics are large, are equivalent in magnitude to those in the north temperate-zone regions, and are in fact far greater than those in the Arctic, even though tropical temperature change has been relatively small. Because of temperature’s nonlinear effects on metabolism, tropical organisms, which constitute much of Earth’s biodiversity, should be profoundly affected by recent and projected climate warming 2 , 13 , 14 .

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/158/670 / 631/443 / 704/106/694 / Animal and plant ecology / Animal, plant and microbial ecology / Animals / Biodiversity / Biological and medical sciences / Biological diversity / Body Temperature / Body Weight / Climate change / Climatology. Bioclimatology. Climate change / Earth, ocean, space / Energy Metabolism / Environmental aspects / Estimates / Exact sciences and technology / External geophysics / Fundamental and applied biological sciences. Psychology / General aspects / Genetics / Geography / Global warming / Global Warming - statistics & numerical data / Humanities and Social Sciences / Internationality / letter / Metabolism / Meteorology / multidisciplinary / Organisms / Physiological aspects / Physiology / Reptiles & amphibians / Science / Science (multidisciplinary) / Seasons / Synecology / Temperature / Tropical Climate / Tropical environments