Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Warming most evident at high latitudes, but greatest impact will be in tropics

15.08.2005


The impact of global warming has become obvious in high latitude regions, including Alaska, Siberia and the Arctic, where melting ice and softening tundra are causing profound changes. But, contrary to popular belief, the most serious impact in the next century likely will be in the tropics, says a group of researchers headed by a University of Washington ecologist.



Scientists have noted warming at higher latitudes that already appears to be causing some flowers to bloom earlier than usual and seems to be altering some wildlife migration and hibernation patterns.

"You see this and you think the higher latitudes are really being hammered by climate change. We are arguing that this might not be true," said Joshua Tewksbury, a UW assistant professor of biology. "To predict the impact of climate change, we need to know the amount of change and how organisms are able to tolerate that change. Previous research has focused on change alone and ignored tolerance."


The more dramatic impact could actually be in the moist tropics, despite modeling that indicates temperatures there will warm just 2 or 3 degrees by 2100 compared with 6 degrees or more at higher latitudes, Tewksbury said. That is because organisms in the tropics normally do not experience much temperature variation because there is very little seasonality, so even small temperature shifts can have a much larger impact than similar shifts in regions with more seasonal climates.

"Temperatures in the tropics don’t fluctuate that much, so the relatively small temperature shifts predicted by climate change models will be very large in relation to what organisms are adapted to tolerate," he said. "It’s only going to be perhaps a 2-degree change, but in many tropical areas organisms have never experienced a 2-degree change."

By contrast, higher latitudes can have vast temperature fluctuations from hot summers to cold winters, and so plants and animals already are adapted to a wide range of temperatures. For example, it is not unusual for temperatures in Alaska’s interior to reach far below zero in the winter and into the mid-70s during the summer. Flowers that bloom earlier and animals that change their hibernation or migration patterns in response to warming temperatures could be an illustration of the adaptability of life at higher latitudes.

Tewksbury’s group collected studies that examined several closely related populations of plants, animals and insects to determine how the populations tolerated changing temperatures. Then they developed models based on the average between a region’s highest temperature in the warmest month of the year and lowest temperature in the coldest month and programmed the region’s expected temperature changes because of climate warming.

"What we find is that organisms in the tropics have very low tolerance," he said. "The evidence suggests that the range of temperatures an organism experiences dictates its tolerance to changing climate, or defines the temperature envelope in which it can live."

Tewksbury will present the findings Friday at the Ecological Society of America’s annual meeting in Montreal. Collaborators include Raymond Huey, a UW biology professor, and UW biology doctoral students David Haak, Paul Martin and Kimberly Sheldon, who is lead author for the work.

Tewksbury noted that while direct estimates of tolerance are not available for all organisms or for all regions of the globe, there is good information on the degree of seasonal temperature fluctuation worldwide. That seasonality, he said, can be used to predict how well organisms will tolerate climate change.

The findings also imply that warming could forever alter life on Earth because the vast majority of species live in the tropics and many could be driven to extinction because of their inability to adapt.

"Evolution only happens if you don’t go extinct. From an evolutionary standpoint, a model of the climate change impact reflects a race between adaptation and extinction," Tewksbury said. "Climate models project 6 degree temperature shifts in temperate zones during the next 90 years and 2 to 3 degrees in equatorial climates. That is such a rapid change that longer-lived organisms such as trees will have very little opportunity for adaptation – survival might be a matter of tolerance alone. In contrast, for an insect that has three generations a year the evolution of tolerance might play a larger role.

"It’s kind of a bleak outlook for tropical organisms, and it shows how the lack of seasonal temperature variation can magnify the impact of climate warming."

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu

More articles from Ecology, The Environment and Conservation:

nachricht Species may appear deceptively resilient to climate change
24.11.2017 | University of California - Davis

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>