August 18, 2011 — andyextance

Life on Earth is creeping to cooler locations up to three times more quickly than previously thought as it strives to survive the warming climate. That’s what Chris Thomas from the University of York, UK, and colleagues have found after updating a prior study with measurements published over the last eight years. “We estimated that, on average, species have been moving away from the Equator towards the poles at 17.6 kilometres per decade,” Thomas told Simple Climate. “Because there are differences among studies, we can conclude that the true rate lies between 11.8 and 23.4 kilometres per decade. Even the lower value is considerably larger than the previously-published best estimate.” Thomas noted that this is equivalent to animals and plants shifting away from the Equator at around 20 cm per hour, every hour of the day, every day of the year. “This has been going on for the last 40 years and is set to continue for at least the rest of this century,” he said.

Following changes in where a species can be found over time takes a lot of measuring, meaning that most studies just look at a few different plants, insects or animals. However, in 2003, Camille Parmesan, a lead author for the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), and Gary Yohe analysed previously recorded range data on 99 species. They found shifts averaging 6.1 km per decade towards the poles. Writing in a paper to be published in top research journal Science on Friday, Thomas’ team has brought that work up to date. “We were aware that a considerable amount of literature had been published since,” Thomas said. “We also thought that there was an opportunity to establish a stronger link between the level of climate warming and the responses.”

127 years of data

Together with fellow York scientists, and compatriots from Durham University and the Centre for Ecology and Hydrology, Thomas looked at data going back as far as 1880, up to as recently as 2007. That included some of their own previous work, like the study that showed moths had on average moved 67 metres uphill on Mount Kinabalu in Borneo in 42 years, along with other researchers’. They looked at distance from the poles for 764 species and the height above sea level for 1367 species, with many being included in both groups. The largest challenge in doing this was how to bring together information that may originally have been presented in very different ways. “We sometimes had to go back to the raw data, or ask colleagues to share their data with us,” Thomas explained.

As well as getting nearer the poles, they found that on average species were climbing to higher elevations by 12.2 metres per decade. Thomas underlined that this analysis is the first to show that faster movement of species range is linked with rates of regional warming. And while on average how much they move did match what might be expected to keep the temperatures they experience constant, within that there was wide variation. Some movement came from retreating where it’s too hot and expanding where it’s no longer too cold. Other species stayed where they had previously been, but with numbers declining where it’s hotter and increasing where it’s cooler. But within this, a minority actually moved in the opposite direction to that expected, with around one in five species moving towards the equator, and one quarter moving downhill. “Species have many different characteristics, including their abilities to move around, the availability of habitats, and their sensitivities to different aspects of the climate, like new extreme events,” Thomas said. “These different sensitivities to climate and other factors means that not all species respond in exactly the same way to climate change.”

Nature leads, governments lag

The overall average figures, and the fact the greatest distances moved are seen where there is the highest warming, paint a bleak overall picture. “The rapid responses that species are showing implies that many are likely to be steaming towards extinction,” Thomas warned. “But we have no globally-agreed list of which are most threatened by climate change, and no globally-agreed strategy for trying to help them. Meanwhile, most governments are preoccupied with getting world economies back up and running. That will generate yet more greenhouse gas emissions and will ensure that the situation deteriorates.”

However, Thomas did concede that more information is needed before it can be said that this gloomy scenario holds true across the whole planet. That’s because most of the measurements his team used come from the UK, with the rest largely from other developed countries. “These estimates apply to Europe and North America, with only limited data available from elsewhere in the world,” he said. “We do not know if these rates apply, for example, to the lowland tropics, where changes in rainfall may be as important as changes in temperature. We would of course prefer it if more data were available from a wider range of taxonomic groups, and from more parts of the world.”