Research suggests autumn is ending later in the northern hemisphere

A press release from the University of Southampton: A study ... suggests that on average the end of Autumn is taking place later in the year and Spring is starting slightly earlier. A team of researchers examined satellite imagery covering the northern hemisphere over a 25 year period (1982 - 2006), and looked for any seasonal changes in vegetation by making a measure of its ‘greenness’. They examined in detail, at daily intervals, the growth cycle of the vegetation – identifying physical changes such as leaf cover, colour and growth.

The project was led by University of Southampton Professor of Geography Peter Atkinson, who worked with his colleague Dr Jadunandan Dash and in collaboration with Professor Jeganathan Chockalingam from the Department of Remote Sensing at the Birla Institute of Technology in India.

Professor Atkinson says: “There is much speculation about whether our seasons are changing and if so, whether this is linked to climate change. Our study is another significant piece in the puzzle, which may ultimately answer this question.”

The team was able to examine the data for specific vegetation types: ‘mosaic’ vegetation (grassland, shrubland, forest and cropland); broad-leaved deciduous forest; needle-leaved evergreen forest; needle-leaved deciduous and evergreen forest; mixed broad-leaved and needle-leaved forest; and mixed-forest, shrubland and grassland. They analysed data across all the groups, recognising that forests which have not changed size due to human intervention, for example through forestry or farming, provide the most reliable information on vegetation response to changes in our climate.

The most pronounced change found by the researchers was in the broad-leaved deciduous and needleleaved deciduous forest groups, showing that Autumn is becoming significantly later. This delay in the signs of Autumn was generally more pronounced than any evidence for an earlier onset of Spring, although there is evidence across the groups that Spring is arriving slightly earlier.

Professor Peter Atkinson comments: “Previous studies have reported trends in the start of Spring and end of Autumn, but we have studied a longer time period and controlled for forest loss and vegetation type, making our study more rigorous and with a greater degree of accuracy....

Fall foliage in Ontario, shot by aiko99ann, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license

Seychelles’ idyllic habitat at risk from climate change

Dawn (Pakistan) via AFP: Bursts of torrential rain lash the idyllic white beaches of the Seychelles, where conservationists fear that rare species such as the giant tortoise are at severe risk from climate change. As changing season patterns bring harsher storms and much longer dry spells, international organisations are helping fight climate change in the tiny nation, the only one in the world where 50 per cent of the land is a nature reserve.

“The seasons are merging, there’s more rain but in short bursts, with long dry periods. Drinking water dries up and the climate plays havoc with breeding and feeding patterns,” said Seychelles climate change expert Rolph Payet.

Recognising the risks, the United Nations Development Programme and Global Environment Facility have approved $8.7 million this year for climate change adaptation projects in the Indian Ocean archipelago.

While part of the funds will go to tackling issues affecting Seychellois people such as drought, the rest is earmarked for further research into protecting the vast array of species from the fallout from global warming. “We have a range of animals at risk, from the rare turtles and tortoises which lay their eggs on our beaches, to mountain frogs and birds such as the Black Parrot, which are endemic to the Seychelles,” Payet said....

Part of Port Launay Marine National Park, Mahe, Seychelles, in the early 1970s. Shot by Photography by Dino Sassi - Marcel Fayon, Photo Eden LTD

Mid-Atlantic suburbs can expect an early spring thanks to the heat of the big city

University of Maryland Center for Environmental Science: If you’ve been thinking our world is more green than frozen these days, you’re right. A recent study has found that spring is indeed arriving earlier – and autumn later – in the suburbs of Baltimore and Washington, D.C. The reason? The urban landscape traps heat in the summer and holds it throughout the winter, triggering leaves to turn green earlier in the spring and to stay green later into autumn. The result is a new, extended growing season.

Scientists used high-resolution satellite data collected over the past 25 years to look at the number days that trees have green leaves in the forests of the Mid-Atlantic. The study found that urban heat islands affected the growing season in areas within 20 miles of the city. As a result, gardeners may have more time to grow their vegetables and plant new varieties.

"This study provides important insight not only into the length of the growing season, but also into changes in water balance and carbon storage that will be accompanying climate change," said Dr. Don Boesch, president of the University of Marlyand Center for Environmental Science.

...“Everything changes when the leaves turn green,” said the study’s lead author Dr. Andrew Elmore of the University of Maryland Center for Environmental Science's Appalachian Laboratory. “Trees start pumping water into the atmosphere. They take carbon dioxide out of the atmosphere. They make sugars and build plant tissue. It’s as if the entire landscape goes from exhaling to inhaling.”

The study also pinpointed other factors that influence the timing of spring and autumn in areas outside the influence of urban heat islands, including the elevation of the landscape, proximity to tidal water, and cold air drainage in small valleys...

Map of growing season length from the University of Maryland website

Spring comes 10 days earlier in changed US climate

Reuters: Spring comes about 10 days earlier in the United States than it did two decades ago, a consequence of climate change that favors invasive species over indigenous ones, scientists said on Tuesday. The phenomenon known as "spring creep" has put various species of U.S. wildlife out of balance with their traditional habitats, from the rabbit-like American pika in the West to the roses and lilies in New England, the environmental experts said in a telephone news briefing.

"The losers tend to be our native plant species," said Charles Davis of Harvard University, who studied plant changes in Concord, Massachusetts, where American conservationist and philosopher Henry David Thoreau lived a century and a half ago.

"Climate change is not affecting species uniformly," Davis said. "Certain groups are hit harder than others, and those species that are not able to respond to climate change ... are being hit the hardest." In Massachusetts, Davis said, those include some of the most charismatic species, such as lilies, orchids, roses and dogwoods.

Based on Thoreau's notes and research by botanists in the area, Davis and other scientists figure that about 30 percent of the plant species Thoreau saw are locally extinct and a further 30 percent are in scarce supply, crowded out by southern invaders that can now thrive in New England. Invasive non-native plants can succeed in a changing climate because some of them are better able to adjust their development…..

Alfons Mucha, Spring, 1896