Tag Archives: Phenology

Rockies flora show climate impact

FOR IMMEDIATE RELEASE An intensive study of the flora of one meadow in the Rocky Mountains of Colorado over nearly 40 years reveals a widespread and consistent pattern of climate-induced change. LONDON, 19 March – Two thirds of alpine flowers have changed their pattern of bloom in response to climate change. Half of them have begun to bloom weeks earlier than normal, one third are reaching their peak bloom well ahead of the traditional almanac date, and others are producing their last blooms later in the year. The season of flowers – that feast for bees and butterflies, and a signal for insectivorous birds to make the most of their moment in the sun – is a month longer than it was four decades ago. This conclusion comes with two qualifications. The first is that it is limited to one meadow in one location in Colorado’s Rocky Mountains in the US. But the other is that it is the product of a meticulous, painstaking 39-year-long study by one researcher. So it follows that since there is not much room for mistake or argument about the pattern in one well-studied location, then a similar pattern probably does apply in many upland temperate zone sites. When David Inouye of the University of Maryland began his research, he was a graduate student who just wanted to know what sources of nectar were available for hummingbirds and bumble bees. So he started counting flowers about 3,000 metres above sea level in Crested Butte, Colorado, at the Rocky Mountain Biological Laboratory. And he carried on.

Big picture

He and colleagues report in the Proceedings of the National Academy of Sciences that they chose 60 common wildflower species – most of them perennial herbs – and they specifically excluded the rarer species because there was not enough data. So they made their judgement on the basis of two million flower counts, during the 39-year interval in which summer air temperatures increased by about 0.4°C per decade and in which the spring snow melt advanced by about 3.5 days per decade. And they also specifically looked at the entire pattern of spring and summer bloom: the big picture of what biologists call phenology, the timing of biological events, in one place. “Most studies rely on first dates like flowering or migration, because they use historical data sets that were not intended as scientific studies”, said Professor Inouye. “First flowering is easy to observe. You don’t have to take the time to count the flowers. So that’s often the only information available. It has taken a lot of effort to get the comprehensive insights needed for this analysis which helps us understand how ecological communities are going to change in the future.” Biologists around the world have begun to use phenological shifts as indicators of climate, and as a basis for future conservation plans, and all of them have observed a pattern of change.

Consistent findings

European researchers confirmed that plants were either moving to higher latitudes, or blooming earlier in response to global warming, and that birds, butterflies and blossoms were actually heading to higher altitudes. Some have used historic observations by one of America’s literary giants as the basis for their research into climate change, and others have looked at the consequences of changes in the plant timetable for the grazers and predators that depend on specific plant communities. But Inouye and colleagues now think that much of the phenological evidence so far has underestimated the numbers of species that have altered their flowering times, and probably overestimated the magnitude of change: what matters in the field or the meadow is the sum of all the changes, and not just the first dates of flowering. Inouye and students divided the meadow into 30 plots, and counted flowers every other day for 39 years, for five months every year. So because of the initial basis of the research, continued for so many years, the scientists had sure data on changes for individual species, including the first flowering, the peak flowering and the last blooms, along with a measure of changes in abundance. The date of first flowering has advanced by six days per decade, the spring peak is on average five days earlier per decade, and the last flower of autumn has been three days later every decade. – Climate News Network

FOR IMMEDIATE RELEASE An intensive study of the flora of one meadow in the Rocky Mountains of Colorado over nearly 40 years reveals a widespread and consistent pattern of climate-induced change. LONDON, 19 March – Two thirds of alpine flowers have changed their pattern of bloom in response to climate change. Half of them have begun to bloom weeks earlier than normal, one third are reaching their peak bloom well ahead of the traditional almanac date, and others are producing their last blooms later in the year. The season of flowers – that feast for bees and butterflies, and a signal for insectivorous birds to make the most of their moment in the sun – is a month longer than it was four decades ago. This conclusion comes with two qualifications. The first is that it is limited to one meadow in one location in Colorado’s Rocky Mountains in the US. But the other is that it is the product of a meticulous, painstaking 39-year-long study by one researcher. So it follows that since there is not much room for mistake or argument about the pattern in one well-studied location, then a similar pattern probably does apply in many upland temperate zone sites. When David Inouye of the University of Maryland began his research, he was a graduate student who just wanted to know what sources of nectar were available for hummingbirds and bumble bees. So he started counting flowers about 3,000 metres above sea level in Crested Butte, Colorado, at the Rocky Mountain Biological Laboratory. And he carried on.

Big picture

He and colleagues report in the Proceedings of the National Academy of Sciences that they chose 60 common wildflower species – most of them perennial herbs – and they specifically excluded the rarer species because there was not enough data. So they made their judgement on the basis of two million flower counts, during the 39-year interval in which summer air temperatures increased by about 0.4°C per decade and in which the spring snow melt advanced by about 3.5 days per decade. And they also specifically looked at the entire pattern of spring and summer bloom: the big picture of what biologists call phenology, the timing of biological events, in one place. “Most studies rely on first dates like flowering or migration, because they use historical data sets that were not intended as scientific studies”, said Professor Inouye. “First flowering is easy to observe. You don’t have to take the time to count the flowers. So that’s often the only information available. It has taken a lot of effort to get the comprehensive insights needed for this analysis which helps us understand how ecological communities are going to change in the future.” Biologists around the world have begun to use phenological shifts as indicators of climate, and as a basis for future conservation plans, and all of them have observed a pattern of change.

Consistent findings

European researchers confirmed that plants were either moving to higher latitudes, or blooming earlier in response to global warming, and that birds, butterflies and blossoms were actually heading to higher altitudes. Some have used historic observations by one of America’s literary giants as the basis for their research into climate change, and others have looked at the consequences of changes in the plant timetable for the grazers and predators that depend on specific plant communities. But Inouye and colleagues now think that much of the phenological evidence so far has underestimated the numbers of species that have altered their flowering times, and probably overestimated the magnitude of change: what matters in the field or the meadow is the sum of all the changes, and not just the first dates of flowering. Inouye and students divided the meadow into 30 plots, and counted flowers every other day for 39 years, for five months every year. So because of the initial basis of the research, continued for so many years, the scientists had sure data on changes for individual species, including the first flowering, the peak flowering and the last blooms, along with a measure of changes in abundance. The date of first flowering has advanced by six days per decade, the spring peak is on average five days earlier per decade, and the last flower of autumn has been three days later every decade. – Climate News Network

Warmth spurs plants to move or bloom earlier

FOR IMMEDIATE RELEASE Plants reacting to climate change have two strategies to deal with increasing warmth: they escape the heat either by moving towards the poles, or by flowering sooner. LONDON, 2 February – Scientists are one step closer to solving one of the puzzles of the natural world’s response to climate change: why one species migrates and another does not. Tatsuya Amano of the University of Cambridge in the UK and colleagues report in the Proceedings of the Royal Society B that there could be a relatively simple explanation, especially for plant behaviour. Those that can make new colonies move north (or south, in the southern hemisphere) to take advantage of changing temperature regimes. Others simply shift the time zone: they flower earlier. The response of flora and fauna to climate change is not a simple one: all sorts of influences are at play, including changes in habitat and in farming methods, in competition from alien introductions, and in the introduction of new kinds of predator. But over the decades, scientists have been able to measure distinctive shifts. In alpine Switzerland, plants, butterflies and birds were all observed to move uphill  as temperatures shifted through the decades. In Britain, some butterfly populations were observed to extend their range northwards while others were less able to take advantage of the opportunity to exploit new territory. Dr Amano and his partners – from Britain, Poland and Germany – looked at a long sequence of historical records to explore the responses of plants. The theory is that over evolutionary time, each species finds a favoured “niche” that suits it best, and occupies it. As climate conditions change, so should the ideal niche, and plants should shift their ground or respond in some other way. All the research requires is a lot of data, collected over hundreds of years.

General principle

“Britain is the ideal study system for this purpose because historical changes in first flowering dates have been estimated for 405 plant species by applying a hierarchical model to almost 400,000 observation records throughout the country”, say the authors, “and records on spatial distribution are available for 6,669 higher plant taxa throughout Britain at two census periods” (a taxon is a group of natural populations judged by taxonomists to constitute a unit). They were able to work from 395,466 records of 405 flowering species collected between 1753 and 2009, held by the UK Phenology Network.They also had access to the oldest set of weather records on the planet, the Central England Temperature series, recording daily temperatures since 1772. By using sophisticated mathematical techniques and a lot of data, the team were able to settle at least one very general principle: if a plant could not take advantage of warmer weather by flowering earlier then there was a greater likelihood that it would shift its range northwards. And there was a complementary relationship: if a plant could not change its ground, it changed its phenology. The finding gives conservation scientists some more general principles to apply. It also reveals some of the characteristics that might indicate how a species might be predicted to respond. The word “might” is important here. Their findings, the authors say, “need to be carefully interpreted, as our models generally had a low explanatory power.” – Climate News Network

FOR IMMEDIATE RELEASE Plants reacting to climate change have two strategies to deal with increasing warmth: they escape the heat either by moving towards the poles, or by flowering sooner. LONDON, 2 February – Scientists are one step closer to solving one of the puzzles of the natural world’s response to climate change: why one species migrates and another does not. Tatsuya Amano of the University of Cambridge in the UK and colleagues report in the Proceedings of the Royal Society B that there could be a relatively simple explanation, especially for plant behaviour. Those that can make new colonies move north (or south, in the southern hemisphere) to take advantage of changing temperature regimes. Others simply shift the time zone: they flower earlier. The response of flora and fauna to climate change is not a simple one: all sorts of influences are at play, including changes in habitat and in farming methods, in competition from alien introductions, and in the introduction of new kinds of predator. But over the decades, scientists have been able to measure distinctive shifts. In alpine Switzerland, plants, butterflies and birds were all observed to move uphill  as temperatures shifted through the decades. In Britain, some butterfly populations were observed to extend their range northwards while others were less able to take advantage of the opportunity to exploit new territory. Dr Amano and his partners – from Britain, Poland and Germany – looked at a long sequence of historical records to explore the responses of plants. The theory is that over evolutionary time, each species finds a favoured “niche” that suits it best, and occupies it. As climate conditions change, so should the ideal niche, and plants should shift their ground or respond in some other way. All the research requires is a lot of data, collected over hundreds of years.

General principle

“Britain is the ideal study system for this purpose because historical changes in first flowering dates have been estimated for 405 plant species by applying a hierarchical model to almost 400,000 observation records throughout the country”, say the authors, “and records on spatial distribution are available for 6,669 higher plant taxa throughout Britain at two census periods” (a taxon is a group of natural populations judged by taxonomists to constitute a unit). They were able to work from 395,466 records of 405 flowering species collected between 1753 and 2009, held by the UK Phenology Network.They also had access to the oldest set of weather records on the planet, the Central England Temperature series, recording daily temperatures since 1772. By using sophisticated mathematical techniques and a lot of data, the team were able to settle at least one very general principle: if a plant could not take advantage of warmer weather by flowering earlier then there was a greater likelihood that it would shift its range northwards. And there was a complementary relationship: if a plant could not change its ground, it changed its phenology. The finding gives conservation scientists some more general principles to apply. It also reveals some of the characteristics that might indicate how a species might be predicted to respond. The word “might” is important here. Their findings, the authors say, “need to be carefully interpreted, as our models generally had a low explanatory power.” – Climate News Network

Thoreau's Walden Pond warms up

FOR IMMEDIATE RELEASE
A corner of the USA forever linked with the name of one of America’s foremost naturalists is changing as the temperature rises. Walden Pond’s familiar vegetation is not what it was in Thoreau’s day.

LONDON, 15 January – Walden, where Henry David Thoreau planted beans on land that had yielded only cinquefoil, blackberries, johnswort and sweet wild fruits, is changing. The trees and shrubs around Walden Pond are now out on average 18 days earlier than 150 years ago, when Thoreau made his observations. And, according to US scientists in the journal New Phytologist, native species could lose out to invasive shrubs such as the Japanese barberry.

Concord in Massachusetts occupies a special place in America’s history: it was the site of the first battle of the war of independence in the 18th century, and later it was immortalised by the writings of Thoreau. But the 19th century author did more than publish elegant observations of the natural economy. He also recorded the first moment when leaves emerged on the trees around Walden Pond, near Concord, and did so for five years between 1852 and 1860.

Caroline Polgar, a student at Boston University, decided to repeat his observations. What she found was surprising: “All species – no exceptions – are leafing out earlier now than they did in Thoreau’s time. On average, woody plants in Concord leaf out 18 days earlier now.”

Between 2009 and 2013 she and her fellow author Amanda Gallinat made observations of 43 woody plants in the region. They also tested 50 species by collecting dormant twigs and placing them in water to see when leaves unfurled in unusually warm laboratory conditions.

Double jeopardy

“We found compelling evidence that invasive shrubs such as Japanese barberry are ready to leaf out quickly once they are exposed to warm temperatures in the lab even in the middle of winter, whereas native shrubs, like highbush blueberry, and native trees, like red maple, need to go through a longer winter chilling period before they can leaf out – and even then their response is slow”, said Gallinat.

“The experiments show that as spring weather continues to warm, it will be the invasive shrubs that will be best able to take advantage of the changing conditions.”

Richard Primack, third author and professor of biology at Boston University, said: “We see that climate change is creating a whole new risk for native plants in Concord.

“Weather in New England is unpredictable, and if plants leaf out early in warm years, they risk having their leaves damaged by a surprise frost. But if plants wait to leaf out until all chance of frost is lost, they may lose their competitive advantage.” – Climate News Network

FOR IMMEDIATE RELEASE
A corner of the USA forever linked with the name of one of America’s foremost naturalists is changing as the temperature rises. Walden Pond’s familiar vegetation is not what it was in Thoreau’s day.

LONDON, 15 January – Walden, where Henry David Thoreau planted beans on land that had yielded only cinquefoil, blackberries, johnswort and sweet wild fruits, is changing. The trees and shrubs around Walden Pond are now out on average 18 days earlier than 150 years ago, when Thoreau made his observations. And, according to US scientists in the journal New Phytologist, native species could lose out to invasive shrubs such as the Japanese barberry.

Concord in Massachusetts occupies a special place in America’s history: it was the site of the first battle of the war of independence in the 18th century, and later it was immortalised by the writings of Thoreau. But the 19th century author did more than publish elegant observations of the natural economy. He also recorded the first moment when leaves emerged on the trees around Walden Pond, near Concord, and did so for five years between 1852 and 1860.

Caroline Polgar, a student at Boston University, decided to repeat his observations. What she found was surprising: “All species – no exceptions – are leafing out earlier now than they did in Thoreau’s time. On average, woody plants in Concord leaf out 18 days earlier now.”

Between 2009 and 2013 she and her fellow author Amanda Gallinat made observations of 43 woody plants in the region. They also tested 50 species by collecting dormant twigs and placing them in water to see when leaves unfurled in unusually warm laboratory conditions.

Double jeopardy

“We found compelling evidence that invasive shrubs such as Japanese barberry are ready to leaf out quickly once they are exposed to warm temperatures in the lab even in the middle of winter, whereas native shrubs, like highbush blueberry, and native trees, like red maple, need to go through a longer winter chilling period before they can leaf out – and even then their response is slow”, said Gallinat.

“The experiments show that as spring weather continues to warm, it will be the invasive shrubs that will be best able to take advantage of the changing conditions.”

Richard Primack, third author and professor of biology at Boston University, said: “We see that climate change is creating a whole new risk for native plants in Concord.

“Weather in New England is unpredictable, and if plants leaf out early in warm years, they risk having their leaves damaged by a surprise frost. But if plants wait to leaf out until all chance of frost is lost, they may lose their competitive advantage.” – Climate News Network

Thoreau’s Walden Pond warms up

FOR IMMEDIATE RELEASE A corner of the USA forever linked with the name of one of America’s foremost naturalists is changing as the temperature rises. Walden Pond’s familiar vegetation is not what it was in Thoreau’s day. LONDON, 15 January – Walden, where Henry David Thoreau planted beans on land that had yielded only cinquefoil, blackberries, johnswort and sweet wild fruits, is changing. The trees and shrubs around Walden Pond are now out on average 18 days earlier than 150 years ago, when Thoreau made his observations. And, according to US scientists in the journal New Phytologist, native species could lose out to invasive shrubs such as the Japanese barberry. Concord in Massachusetts occupies a special place in America’s history: it was the site of the first battle of the war of independence in the 18th century, and later it was immortalised by the writings of Thoreau. But the 19th century author did more than publish elegant observations of the natural economy. He also recorded the first moment when leaves emerged on the trees around Walden Pond, near Concord, and did so for five years between 1852 and 1860. Caroline Polgar, a student at Boston University, decided to repeat his observations. What she found was surprising: “All species – no exceptions – are leafing out earlier now than they did in Thoreau’s time. On average, woody plants in Concord leaf out 18 days earlier now.” Between 2009 and 2013 she and her fellow author Amanda Gallinat made observations of 43 woody plants in the region. They also tested 50 species by collecting dormant twigs and placing them in water to see when leaves unfurled in unusually warm laboratory conditions.

Double jeopardy

“We found compelling evidence that invasive shrubs such as Japanese barberry are ready to leaf out quickly once they are exposed to warm temperatures in the lab even in the middle of winter, whereas native shrubs, like highbush blueberry, and native trees, like red maple, need to go through a longer winter chilling period before they can leaf out – and even then their response is slow”, said Gallinat. “The experiments show that as spring weather continues to warm, it will be the invasive shrubs that will be best able to take advantage of the changing conditions.” Richard Primack, third author and professor of biology at Boston University, said: “We see that climate change is creating a whole new risk for native plants in Concord. “Weather in New England is unpredictable, and if plants leaf out early in warm years, they risk having their leaves damaged by a surprise frost. But if plants wait to leaf out until all chance of frost is lost, they may lose their competitive advantage.” – Climate News Network

FOR IMMEDIATE RELEASE A corner of the USA forever linked with the name of one of America’s foremost naturalists is changing as the temperature rises. Walden Pond’s familiar vegetation is not what it was in Thoreau’s day. LONDON, 15 January – Walden, where Henry David Thoreau planted beans on land that had yielded only cinquefoil, blackberries, johnswort and sweet wild fruits, is changing. The trees and shrubs around Walden Pond are now out on average 18 days earlier than 150 years ago, when Thoreau made his observations. And, according to US scientists in the journal New Phytologist, native species could lose out to invasive shrubs such as the Japanese barberry. Concord in Massachusetts occupies a special place in America’s history: it was the site of the first battle of the war of independence in the 18th century, and later it was immortalised by the writings of Thoreau. But the 19th century author did more than publish elegant observations of the natural economy. He also recorded the first moment when leaves emerged on the trees around Walden Pond, near Concord, and did so for five years between 1852 and 1860. Caroline Polgar, a student at Boston University, decided to repeat his observations. What she found was surprising: “All species – no exceptions – are leafing out earlier now than they did in Thoreau’s time. On average, woody plants in Concord leaf out 18 days earlier now.” Between 2009 and 2013 she and her fellow author Amanda Gallinat made observations of 43 woody plants in the region. They also tested 50 species by collecting dormant twigs and placing them in water to see when leaves unfurled in unusually warm laboratory conditions.

Double jeopardy

“We found compelling evidence that invasive shrubs such as Japanese barberry are ready to leaf out quickly once they are exposed to warm temperatures in the lab even in the middle of winter, whereas native shrubs, like highbush blueberry, and native trees, like red maple, need to go through a longer winter chilling period before they can leaf out – and even then their response is slow”, said Gallinat. “The experiments show that as spring weather continues to warm, it will be the invasive shrubs that will be best able to take advantage of the changing conditions.” Richard Primack, third author and professor of biology at Boston University, said: “We see that climate change is creating a whole new risk for native plants in Concord. “Weather in New England is unpredictable, and if plants leaf out early in warm years, they risk having their leaves damaged by a surprise frost. But if plants wait to leaf out until all chance of frost is lost, they may lose their competitive advantage.” – Climate News Network

Nature adapts to shifting seasons

EMBARGOED till 0001 GMT on Friday 8 February The natural world is already adapting to changes in the seasons, with evidence from the United States that spring is steadily advancing the time of its arrival. LONDON, 8 February – Appalachian spring – and springtime in the Rockies, and mountain greenery too – will tune up a little earlier: up to a month earlier, according to new studies from the United States. Scientists report in Geophysical Research Letters that careful analysis of observations of budburst – that promising moment near the end of winter when green shoots begin to appear on the first trees – show that spring could arrive dramatically earlier by the end of this century. Although meteorologists and climate scientists base their forecasts on the levels of carbon dioxide in the atmosphere and an expected parallel rise in temperatures, a group of observers known as phenologists take another approach. Phenologists – they could be university botanists, or keen amateur gardeners, or government agencies, or schools and colleges, or just citizen scientists – have been recording the behaviour of plants, birds, insects and so on for decades and noting the first bud, the first leaf, the first bloom, the first signs of nesting and so on. And, over the past 30 years, spring in the northern hemisphere has arrived steadily earlier. Since daylight length does not change, the implication is that plants and animals are detecting a steady rise in temperatures and responding ever earlier. Su-Jong Jeong of Princeton University and colleagues looked at data from the USA National Phenology Network for budburst in five tree species at 196 sites in the continental US and fed the data into models for climate change.

Knock-on effects

  They tested these with four climate scenarios and found that on average spring could announce itself 17 days earlier in the future. In the case of specific trees, such as the red maple, budburst could occur anything between eight and 40 days earlier, depending on the part of the country, by 2100. Trees in the northernmost states – Maine, New York, Michigan and Wisconsin – could bud up to 38 days earlier. In the southern states, the effect will be much less pronounced. And, the scientists predict, the “green wave” that rolls north over continental North America with each new spring will also accelerate. It now takes just over 74 days for budburst to spread from the southern states to the Canadian border. By the end of the century, the phenomenon will have shortened to 59 days, they predict. There is a practical aspect: this kind of research is concerned with understanding in detail how the world works, and how changes in temperature might affect ecosystems, which in turn could feed back into climate change. “We expect that climate-driven changes in phenology will have large effects on the carbon budget of US forests and these controls should be included in dynamic global vegetation models,” the authors say.

“…a cold winter is enough to make some people, including many newspaper editors and opinion leaders, doubt the overwhelming scientific consensus on the issue”

But while plants and animals seem to be aware of global warming, humans are much more fickle, according to new research from Canada. Researchers at the University of British Columbia report in Climatic Change that although periods of intense heat can increase concern over the possible effects of climate change, a cold snap can lead to scepticism. Simon Donner and Jeremy McDaniels studied data from national opinion polls taken between 1990 and 2010, and analysed opinion pieces from US journals such as the Wall Street Journal, the New York Times, the Washington Post and USA Today. They then tried to put a value on the relationship between average national temperatures and responses in the polls, as well as the heated – or cool – expressions of opinion in the newspapers. They found that people do tend to “blow hot and cold” according to the evidence around them. When seasons were warmer than normal, Americans were more convinced about human-caused climate change. “The study demonstrates just how much local weather can influence people’s opinions on global warming,” said Professor Donner. “We find that, unfortunately, a cold winter is enough to make some people, including many newspaper editors and opinion leaders, doubt the overwhelming scientific consensus on the issue.” – Climate News Network

EMBARGOED till 0001 GMT on Friday 8 February The natural world is already adapting to changes in the seasons, with evidence from the United States that spring is steadily advancing the time of its arrival. LONDON, 8 February – Appalachian spring – and springtime in the Rockies, and mountain greenery too – will tune up a little earlier: up to a month earlier, according to new studies from the United States. Scientists report in Geophysical Research Letters that careful analysis of observations of budburst – that promising moment near the end of winter when green shoots begin to appear on the first trees – show that spring could arrive dramatically earlier by the end of this century. Although meteorologists and climate scientists base their forecasts on the levels of carbon dioxide in the atmosphere and an expected parallel rise in temperatures, a group of observers known as phenologists take another approach. Phenologists – they could be university botanists, or keen amateur gardeners, or government agencies, or schools and colleges, or just citizen scientists – have been recording the behaviour of plants, birds, insects and so on for decades and noting the first bud, the first leaf, the first bloom, the first signs of nesting and so on. And, over the past 30 years, spring in the northern hemisphere has arrived steadily earlier. Since daylight length does not change, the implication is that plants and animals are detecting a steady rise in temperatures and responding ever earlier. Su-Jong Jeong of Princeton University and colleagues looked at data from the USA National Phenology Network for budburst in five tree species at 196 sites in the continental US and fed the data into models for climate change.

Knock-on effects

  They tested these with four climate scenarios and found that on average spring could announce itself 17 days earlier in the future. In the case of specific trees, such as the red maple, budburst could occur anything between eight and 40 days earlier, depending on the part of the country, by 2100. Trees in the northernmost states – Maine, New York, Michigan and Wisconsin – could bud up to 38 days earlier. In the southern states, the effect will be much less pronounced. And, the scientists predict, the “green wave” that rolls north over continental North America with each new spring will also accelerate. It now takes just over 74 days for budburst to spread from the southern states to the Canadian border. By the end of the century, the phenomenon will have shortened to 59 days, they predict. There is a practical aspect: this kind of research is concerned with understanding in detail how the world works, and how changes in temperature might affect ecosystems, which in turn could feed back into climate change. “We expect that climate-driven changes in phenology will have large effects on the carbon budget of US forests and these controls should be included in dynamic global vegetation models,” the authors say.

“…a cold winter is enough to make some people, including many newspaper editors and opinion leaders, doubt the overwhelming scientific consensus on the issue”

But while plants and animals seem to be aware of global warming, humans are much more fickle, according to new research from Canada. Researchers at the University of British Columbia report in Climatic Change that although periods of intense heat can increase concern over the possible effects of climate change, a cold snap can lead to scepticism. Simon Donner and Jeremy McDaniels studied data from national opinion polls taken between 1990 and 2010, and analysed opinion pieces from US journals such as the Wall Street Journal, the New York Times, the Washington Post and USA Today. They then tried to put a value on the relationship between average national temperatures and responses in the polls, as well as the heated – or cool – expressions of opinion in the newspapers. They found that people do tend to “blow hot and cold” according to the evidence around them. When seasons were warmer than normal, Americans were more convinced about human-caused climate change. “The study demonstrates just how much local weather can influence people’s opinions on global warming,” said Professor Donner. “We find that, unfortunately, a cold winter is enough to make some people, including many newspaper editors and opinion leaders, doubt the overwhelming scientific consensus on the issue.” – Climate News Network