Prehistoric changes in vegetation help predict future of earth's ecosytems
As the last ice age came to an end and the planet warmed, the Earth’s vegetation changed dramatically. The current warming from climate change may drive an equally dramatic change in vegetation within the next 100 to 150 years unless greenhouse-gas emissions are reduced, reports an international research team including UvA researcher Dr William Gosling. The team’s paper ‘Past and future global transformation of terrestrial ecosystems under climate change’ is published now in Science.
‘We found that ecosystems all over the globe experienced big changes,’ said Connor Nolan, a doctoral candidate in the University of Arizona and lead author of the paper. ‘About 70% of those sites experienced large changes in the species that were there and what the vegetation looked like.’ The researchers used their analysis of how vegetation changed after the last ice age to project how much current ecosystems could change in the 21st century and beyond as global warming progresses.
Large-scale study approach
The analysis required synthesizing information from published reports for 594 sites covering every continent except Antarctica. The study is the most comprehensive compilation of vegetation and other ecological data and uses previously published research that calculated how the temperature changed from the ice ages to the pre-industrial era for sites throughout the globe. For each of the sites, the authors enlisted experts to determine whether the degree of vegetation change since the last ice age was low, moderate or large. Dr William Gosling, palaeoecologist at the UvA Institute for Biodiversity and Ecosystem Dynamics (IBED) was involved in this study by carrying out the expert assessments of the neotropical region.
The experts classified more than 67 percent of the vegetation changes as high and at least another 26 percent as moderate. The changes were especially pronounced in the mid-to-high latitudes in North America, Europe and South America -- regions that were most heavily glaciated and therefore had warmed the most since the ice ages.
Risks of temperature rise
The team found that the regions of the world that had the biggest temperature increases since the ice ages also had the greatest changes in vegetation. Knowing the relationship between temperature change and the degree of vegetation change allowed the researchers to determine how ecosystems might change under various greenhouse-gas emissions models. ‘We used the results from the past to look at the risk of future ecosystem change,’ Nolan said. ‘We find that as temperatures rise there are bigger and bigger risks for more ecosystem change.’
‘The study is important because it shows how global ecosystems have responded to high magnitude climate change since the last ice age. The last deglaciation saw a warming equivalent in magnitude to projections of warming over the coming centuries if green-house gas emissions are not reduced substantially,’ says Gosling. These changes would threaten global biodiversity and derail vital services that nature provides to humanity, such as water security, carbon storage and recreation.
Prehistoric Changes in Vegetation Help Predict Future of Earth’s Ecosystems. Science (2018). DOI: 10.1126/science.aan5360