Tag Archives: Seasonal fluctuations

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Early springs surprise many species

FOR IMMEDIATE RELEASE As seasonal change suffers ever more disruption, many species are struggling to adapt quickly enough. LONDON, 7 April – Spring is arriving earlier. This is not necessarily welcome news for Arctic creatures or the roe deer of France. It could be awkward for flower festival organisers as well. Julienne Stroeve of the US National Snow and Ice Data Centre and colleagues will report in Geophysical Research Letters that the length of the Arctic melt season is growing by several days each decade. When the melt starts earlier, the Arctic Ocean absorbs more radiation: enough in some places to melt four feet in thickness from the Arctic ice cap. “The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the oceans and increase ice melt during the summer, overall weakening the sea ice cover,” says Stroeve. The Arctic sea ice has now been in decline for four decades. The seven lowest September sea ice extents in the satellite record have all occurred in the last seven years. A new examination of satellite imagery and data from 1979 to the present shows that the Beaufort and Chukchi Seas are freezing up between six and 11 days later per decade. But the earlier melt is more ominous than the later freeze: the sun is higher and brighter, and delivers more warmth to the seas.

Festival disruption

The earlier spring presents no problems for many plants but it may not be much fun for the organisers of flower festivals who like to announce their events well in advance. Tim Sparks of Coventry University reports in the journal Climate Research that over its 46-year history, the Thriplow Daffodil Weekend in Cambridgeshire in eastern England has been forced to bring its dates forward by 26 days. The event can attract up to 10,000 visitors, and has raised £300,000 (US $500,000) for charity, so it clearly helps the organisers to set up some advance publicity. Since 1969, mean temperatures in March and April in the UK have risen by 1.8°C. “The study represents one of the first solid pieces of evidence of flower tourism having to adapt to climate change,” said Professor Sparks. “The issues faced by Thriplow are a microcosm of the wider picture.” Flower festivals may be able to adapt. Sadly, the roe deer of Champagne have yet to get the message about climate change. To flourish, both nectar seekers and herbivores have to time their breeding patterns to the surge in plant growth. Three French scientists looked at records of a population of roe deer in the Champagne region of France, and found that although spring has been arriving increasingly earlier, the fawns are being born at around the same dates as they were 27 years ago, and their survival rate is falling, they report in the Public Library of Science journal PLOS Biology. Overall, the roe deer population in the region is also in decline. Great tits have kept up with climate change, because reproduction is cued by temperature, so they are around at the same time as the explosion in food sources. What sets the biological pace for roe deer is day length, the authors think, and this is not affected by climate change. – Climate News Network

FOR IMMEDIATE RELEASE As seasonal change suffers ever more disruption, many species are struggling to adapt quickly enough. LONDON, 7 April – Spring is arriving earlier. This is not necessarily welcome news for Arctic creatures or the roe deer of France. It could be awkward for flower festival organisers as well. Julienne Stroeve of the US National Snow and Ice Data Centre and colleagues will report in Geophysical Research Letters that the length of the Arctic melt season is growing by several days each decade. When the melt starts earlier, the Arctic Ocean absorbs more radiation: enough in some places to melt four feet in thickness from the Arctic ice cap. “The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the oceans and increase ice melt during the summer, overall weakening the sea ice cover,” says Stroeve. The Arctic sea ice has now been in decline for four decades. The seven lowest September sea ice extents in the satellite record have all occurred in the last seven years. A new examination of satellite imagery and data from 1979 to the present shows that the Beaufort and Chukchi Seas are freezing up between six and 11 days later per decade. But the earlier melt is more ominous than the later freeze: the sun is higher and brighter, and delivers more warmth to the seas.

Festival disruption

The earlier spring presents no problems for many plants but it may not be much fun for the organisers of flower festivals who like to announce their events well in advance. Tim Sparks of Coventry University reports in the journal Climate Research that over its 46-year history, the Thriplow Daffodil Weekend in Cambridgeshire in eastern England has been forced to bring its dates forward by 26 days. The event can attract up to 10,000 visitors, and has raised £300,000 (US $500,000) for charity, so it clearly helps the organisers to set up some advance publicity. Since 1969, mean temperatures in March and April in the UK have risen by 1.8°C. “The study represents one of the first solid pieces of evidence of flower tourism having to adapt to climate change,” said Professor Sparks. “The issues faced by Thriplow are a microcosm of the wider picture.” Flower festivals may be able to adapt. Sadly, the roe deer of Champagne have yet to get the message about climate change. To flourish, both nectar seekers and herbivores have to time their breeding patterns to the surge in plant growth. Three French scientists looked at records of a population of roe deer in the Champagne region of France, and found that although spring has been arriving increasingly earlier, the fawns are being born at around the same dates as they were 27 years ago, and their survival rate is falling, they report in the Public Library of Science journal PLOS Biology. Overall, the roe deer population in the region is also in decline. Great tits have kept up with climate change, because reproduction is cued by temperature, so they are around at the same time as the explosion in food sources. What sets the biological pace for roe deer is day length, the authors think, and this is not affected by climate change. – Climate News Network

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Warming means wetter weather – and drier

EMBARGOED till 1800 Sunday 3 March Researchers say they have found evidence that in the last 30 years wet seasons have been becoming wetter and dry ones drier, as changes in the seasonal precipitation cycle continue. LONDON, 3 March – Welcome to the see-saw world of climate change. Rainy seasons will get rainier. Dry seasons will tend to become more parched. Even if the total annual rainfall does not change very much, the seasonal cycles will – with obvious consequences. Floods and droughts will become more frequent, according to Chia Chou of the University of Taipei, and colleagues from Taiwan and California. Like all pronouncements about the future, this one comes with caveats: the research is based on climate simulations of future warming, and the forecasts are only as good as the data fed into such simulations. But the authors start with a trend they can already measure: they report in Nature Geoscience that they looked at rainfall data between 1979 and 2010 and found that the wet seasons were already clearly getting wetter, at the rate of almost a millimetre a day per century, while the dry seasons became drier with just over half a millimetre less in rainfall per day per century.

Affecting drought and flood frequency

  And the gap between wet and dry seasons was widening at a rate of 1.47 millimetres per day per century. All three trends, they report, “are significant at the 99% confidence level.” In the real world most of us experience, it’s hard to be sure that rainy spells are rainier, and dry seasons are drier: that is because, as the authors concede, global rainfall patterns are “spatially complex”. But there is general agreement that such changes are taking place, with good physical reasons for doing so: a warmer world means more evaporation, and more precipitation. Furthermore, the authors say, simulations predict such a pattern and observations confirm it. “The effect is often termed the thermodynamic contribution, or the rich-get-richer mechanism”, they write. “Even if the total amount of annual rainfall does not change significantly, the enhancement in the seasonal precipitation cycle could have marked consequences for the frequency of droughts and floods.” – Climate News Network

EMBARGOED till 1800 Sunday 3 March Researchers say they have found evidence that in the last 30 years wet seasons have been becoming wetter and dry ones drier, as changes in the seasonal precipitation cycle continue. LONDON, 3 March – Welcome to the see-saw world of climate change. Rainy seasons will get rainier. Dry seasons will tend to become more parched. Even if the total annual rainfall does not change very much, the seasonal cycles will – with obvious consequences. Floods and droughts will become more frequent, according to Chia Chou of the University of Taipei, and colleagues from Taiwan and California. Like all pronouncements about the future, this one comes with caveats: the research is based on climate simulations of future warming, and the forecasts are only as good as the data fed into such simulations. But the authors start with a trend they can already measure: they report in Nature Geoscience that they looked at rainfall data between 1979 and 2010 and found that the wet seasons were already clearly getting wetter, at the rate of almost a millimetre a day per century, while the dry seasons became drier with just over half a millimetre less in rainfall per day per century.

Affecting drought and flood frequency

  And the gap between wet and dry seasons was widening at a rate of 1.47 millimetres per day per century. All three trends, they report, “are significant at the 99% confidence level.” In the real world most of us experience, it’s hard to be sure that rainy spells are rainier, and dry seasons are drier: that is because, as the authors concede, global rainfall patterns are “spatially complex”. But there is general agreement that such changes are taking place, with good physical reasons for doing so: a warmer world means more evaporation, and more precipitation. Furthermore, the authors say, simulations predict such a pattern and observations confirm it. “The effect is often termed the thermodynamic contribution, or the rich-get-richer mechanism”, they write. “Even if the total amount of annual rainfall does not change significantly, the enhancement in the seasonal precipitation cycle could have marked consequences for the frequency of droughts and floods.” – Climate News Network