Transient effects of climate on vegetation dynamics: Satellite observations

Ecological modellers are preparing to address how the biosphere may respond to decadal- to century-scale changes in the Earth's environmental system. This endeavour has revealed a question for which no immediate answer is readily available: how do ecosystems respond dynamically to climate variations? This question is explored with a 10 + year record of global vegetation dynamics recorded by a satellite remote sensing observatory. It is found that the average geography of observed vegetation patterns is well explained by continental-scale patterns of climatology in both North and South America and Africa. However, there is little relation observed in inter-annual deviations of the two data sets, with the possible exception of marginal cold and/or dry environments. Evidence from the African continent suggests that even in marginal environments the apparent correlation between climate and the satellite vegetation measurements varies from year to year indicating some persistence or lag between vegetation activity and climate dynamics. These observations lead to a conceptual model of vegetation amount and activity in the presence of climate variation. Testing the model is an important objective that could be addressed by the Global Change and Terrestrial Ecosystems, International Geosphere-Biosphere Project over the next decade.