Friday, 14 September 2012

A Warming Earth Creates More Biodiversity, But Only In The Long Term

Global warming is a scientific reality, whether we want to ascribe it to natural processes or man-made effects. One of the questions raised by this phenomenon is how will
it affect biodiversity on the planet.

A new study by the Universities of York, Glasgow and Leeds, reveals answers that conflict with past studies. The new research involved analysis of fossil and geological records going back 540 million years and it suggests that biodiversity on Earth generally increases as the planet warms.

The catch, according to the researchers, is that this increase in biodiversity depends on the evolution of new species over millions of years. This is normally accompanied by extinctions of existing species.

The study, published in Proceedings of the National Academy of Sciences, suggests that current warming trends are unlikely to boost global biodiversity in the short term because of the long timescales necessary for new forms to evolve. The speed of current changes in temperature is actually expected to cause diversity loss, instead.

This research is a refinement of an earlier study that analyzed biodiversity over the same time interval, but with a less sophisticated data set. The earlier study concluded that a warming climate would lead to drops in overall biodiversity. Using the improved dataset, the research team re-examined patterns of marine invertebrate biodiversity over the last 540 million years.

Dr Peter Mayhew, of the Department of Biology at York, said, “The improved data give us a more secure picture of the impact of warmer temperatures on marine biodiversity and they show that, as before, there is more extinction and origination in warm geological periods. But, overall, warm climates seem to boost biodiversity in the very long run, rather than reducing it.”

Dr Alistair McGowan, of the School of Geographical and Earth Sciences at the University of Glasgow said, “The previous findings always seemed paradoxical. Ecological studies show that species richness consistently increases towards the Equator, where it is warm, yet the relationship between biodiversity and temperature through time appeared to be the opposite. Our new results reverse these conclusions and bring them into line with the ecological pattern.”

Professor Tim Benton, of the Faculty of Biological Sciences at the University of Leeds, added: “Science progresses by constantly re-examining conclusions in the light of better data. Our results seem to show that temperature improves biodiversity through time as well as across space. However, they do not suggest that current global warming is good for existing species. Increases in global diversity take millions of years, and in the meantime we expect extinctions to occur.”

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