Tag Archives: cities

Asia’s cities are worst hit in warming world

Climate change, water shortage and pollution are worst for Asia’s cities, researchers say. The rest of us have a lucky escape.

LONDON, 17 May, 2021 – It’s bad news for residents of Jakarta. People living in Delhi, Chennai or Wuhan do not fare much better. A new study has found that a wide range of environmental and climate change threats are worst for Asia’s cities, with the rest of the planet getting off more lightly.

The study, by the analysis and forecasting group Verisk Maplecroft, looks primarily at the risks posed to businesses operating and investing in various urban centres.

Based on such factors as pollution, a lack of water, extreme heat and general vulnerability to climate change, 99 of the 100 most risk-prone cities in the world are in Asia, with the Indonesian capital Jakarta topping the list and cities in India close behind.

Jakarta, with a population of more than 10.5 million people, is sinking. Like many coastal cities round the world, it is vulnerable to sea level rise.
Built on what was once a swamp, the city has serious water supply problems as well, and the air is severely polluted.

“The reality for most cities is of widespread productivity losses, skyrocketing cooling costs, and a grim toll of heat-related disease”

Little can be done: the Indonesian government plans to shut up shop and move the capital to East Kalimantan on the island of Borneo.

Air and water pollution are particularly acute problems in India’s cities. In its risk index, the study ranks Delhi, Chennai, Agra and Kanpur in the top ten of the world’s cities most at risk of environmental disaster and climate change.

Several cities in China, along with Manila in the Philippines, Bangkok in Thailand and Karachi in Pakistan score badly. Nor are cities outside Asia immune from the growing environmental and climate crisis.

“Londoners might envisage warm days in the park and an Italian café culture, but the reality for most cities is of widespread productivity losses, skyrocketing cooling costs, and a grim toll of heat-related disease”, says the study.

Clean Cairo?

The business sector has to be aware of what’s happening and assess the risks of locating and investing in various urban centres. “How well global organisations manage the escalating environmental and climate crisis is now one of the most critical factors determining their long-term resilience”, says Verisk Maplecroft.

Legal issues have to be considered. “As the pace picks up on carbon regulations, legal liabilities related to climate are also becoming more mainstream”, the study says.

Cities in Canada and New Zealand generally perform well on the Verisk Maplecroft index. Many European cities also achieve a good rating.

Istanbul in Turkey and Jeddah in Saudi Arabia perform badly while, perhaps surprisingly, the Egyptian capital Cairo – a city of nearly 10 million – performs better, mainly due to its cleaner air and greater access to water supplies.

Northern attraction

Elsewhere In Africa, the teeming metropolises of Lagos in Nigeria and Kinshasa in the Democratic Republic of Congo have a low rating. In South America, the desert city of Lima, the Peruvian capital, is facing severe water shortages and other environmental problems.

There is more and more evidence that fish and many other creatures are moving north as ocean and land temperatures rise. Plant life is also trying to adjust to global warming.

One of the overall messages of the study seems to be that, however grim the problems of Asia’s cities, when it comes to looking for cities to live in, we humans should also be moving northwards.

Helsinki, the capital of Finland, scores well on the study’s index. Vancouver and Ottawa in Canada would not be a bad bet. Krasnoyarsk in Siberia looks OK.

And there’s good news for those heading for Glasgow for the big COP-26 climate conference later this year. The Scottish city – not renowned for warm, moisture-free days – is among those in the world least exposed to the dangers of climate change, says the study. – Climate News Network

Climate change, water shortage and pollution are worst for Asia’s cities, researchers say. The rest of us have a lucky escape.

LONDON, 17 May, 2021 – It’s bad news for residents of Jakarta. People living in Delhi, Chennai or Wuhan do not fare much better. A new study has found that a wide range of environmental and climate change threats are worst for Asia’s cities, with the rest of the planet getting off more lightly.

The study, by the analysis and forecasting group Verisk Maplecroft, looks primarily at the risks posed to businesses operating and investing in various urban centres.

Based on such factors as pollution, a lack of water, extreme heat and general vulnerability to climate change, 99 of the 100 most risk-prone cities in the world are in Asia, with the Indonesian capital Jakarta topping the list and cities in India close behind.

Jakarta, with a population of more than 10.5 million people, is sinking. Like many coastal cities round the world, it is vulnerable to sea level rise.
Built on what was once a swamp, the city has serious water supply problems as well, and the air is severely polluted.

“The reality for most cities is of widespread productivity losses, skyrocketing cooling costs, and a grim toll of heat-related disease”

Little can be done: the Indonesian government plans to shut up shop and move the capital to East Kalimantan on the island of Borneo.

Air and water pollution are particularly acute problems in India’s cities. In its risk index, the study ranks Delhi, Chennai, Agra and Kanpur in the top ten of the world’s cities most at risk of environmental disaster and climate change.

Several cities in China, along with Manila in the Philippines, Bangkok in Thailand and Karachi in Pakistan score badly. Nor are cities outside Asia immune from the growing environmental and climate crisis.

“Londoners might envisage warm days in the park and an Italian café culture, but the reality for most cities is of widespread productivity losses, skyrocketing cooling costs, and a grim toll of heat-related disease”, says the study.

Clean Cairo?

The business sector has to be aware of what’s happening and assess the risks of locating and investing in various urban centres. “How well global organisations manage the escalating environmental and climate crisis is now one of the most critical factors determining their long-term resilience”, says Verisk Maplecroft.

Legal issues have to be considered. “As the pace picks up on carbon regulations, legal liabilities related to climate are also becoming more mainstream”, the study says.

Cities in Canada and New Zealand generally perform well on the Verisk Maplecroft index. Many European cities also achieve a good rating.

Istanbul in Turkey and Jeddah in Saudi Arabia perform badly while, perhaps surprisingly, the Egyptian capital Cairo – a city of nearly 10 million – performs better, mainly due to its cleaner air and greater access to water supplies.

Northern attraction

Elsewhere In Africa, the teeming metropolises of Lagos in Nigeria and Kinshasa in the Democratic Republic of Congo have a low rating. In South America, the desert city of Lima, the Peruvian capital, is facing severe water shortages and other environmental problems.

There is more and more evidence that fish and many other creatures are moving north as ocean and land temperatures rise. Plant life is also trying to adjust to global warming.

One of the overall messages of the study seems to be that, however grim the problems of Asia’s cities, when it comes to looking for cities to live in, we humans should also be moving northwards.

Helsinki, the capital of Finland, scores well on the study’s index. Vancouver and Ottawa in Canada would not be a bad bet. Krasnoyarsk in Siberia looks OK.

And there’s good news for those heading for Glasgow for the big COP-26 climate conference later this year. The Scottish city – not renowned for warm, moisture-free days – is among those in the world least exposed to the dangers of climate change, says the study. – Climate News Network

Natural hotspots lose ground to farms and cities

Nature concentrates its riches in selected spots. Save those natural hotspots, and you could save biodiversity. Really?

LONDON, 6 November, 2020 − Nations that signed up to preserve biodiversity − the richness of living things in the world’s forests, grasslands and wetlands − are not doing so very well: in one generation they have altered, degraded or cleared at least 1.48 million square kilometres of natural hotspots unusually rich in wildlife.

This is an area in total larger than South Africa, or Peru. It is almost as large as Mongolia. And importantly, this lost landscape adds up to 6% of the scattered ecosystems that make up the world’s biodiversity hotspots.

The biodiversity hotspot was defined, in 2000, as an area of land home to at least 0.5% of the world’s endemic species of plant. That means that a tract of marsh, savannah, upland or forest that may have already lost 70% of its cover is host to at least 1500 species native to that landscape and nowhere else.

Researchers at the time calculated that 44% of all vascular plants and 35% of all amphibians, reptiles, birds and mammals could be concentrated in just 25 such hotspots on the world’s continents and islands.

The hotspot count has since been increased to 34. But the message has remained. Focus on preserving and protecting these areas and you have a “silver bullet” strategy for conserving wildlife worldwide.

First such inventory

But, say scientists in the journal Frontiers in Ecology and the Environment, between 1992 and 2015 much of this precious wilderness has been consumed by agriculture, or paved by sprawling cities.

Their analysis of high resolution land-cover maps made by the European Space Agency is the first to try to look at the global inventory of hotspots, over a time frame of almost a quarter century.

“We see that not even focusing protection on a small range of areas worked well,” said Francesco Cherubini of the Norwegian University of Science and Technology, who with colleagues carried out the research. “There was major deforestation even in areas that were supposed to be protected.”

Two fifths of the lost landscapes were in forests, and agriculture accounted for most of this loss, particularly in the tropical forests of Indonesia, the Indo-Burma region and Mesoamerica. Five per cent of the lost hotspots were in areas formally declared as under state protection.

“The soils in these areas are very fertile, and agricultural yields can be very high. So it’s very productive land from an agricultural point of view, and attractive to farmers and local authorities that have to think about rising local incomes by feeding a growing population,” Professor Cherubini said.

“Not even focusing protection on a small range of areas worked well … There was major deforestation even in areas that were supposed to be protected.”

But most of the lost land went not to feeding people: it went instead to producing palm oil or soybeans for cattle feed. And local people may not have benefited: the change was driven by commercial agribusiness.

“You have these big companies that are making these investments, with high risks of land overexploitation and environmental degradation. The local population might get some benefits from revenues, but not much.”

The tension between hungry humans and vulnerable wilderness continues. Once again, such research supports a call for the people of the planet to consider a switch to plant-based diets, a switch that could contain climate change and preserve the natural capital on which all life depends. But many of those rich habitats are in some of the poorest countries.

“We need to be able somehow to link protection to poverty alleviation, because most of the biodiversity hotspots are in underdeveloped countries and it’s difficult to go there and say to a farmer, ‘Well, you need to keep this forest − don’t have a rice paddy or a field to feed your family’”, Professor Cherubini said.

“We need to also make it possible for the local communities to benefit from protection measures. They need income, too.” − Climate News Network

Nature concentrates its riches in selected spots. Save those natural hotspots, and you could save biodiversity. Really?

LONDON, 6 November, 2020 − Nations that signed up to preserve biodiversity − the richness of living things in the world’s forests, grasslands and wetlands − are not doing so very well: in one generation they have altered, degraded or cleared at least 1.48 million square kilometres of natural hotspots unusually rich in wildlife.

This is an area in total larger than South Africa, or Peru. It is almost as large as Mongolia. And importantly, this lost landscape adds up to 6% of the scattered ecosystems that make up the world’s biodiversity hotspots.

The biodiversity hotspot was defined, in 2000, as an area of land home to at least 0.5% of the world’s endemic species of plant. That means that a tract of marsh, savannah, upland or forest that may have already lost 70% of its cover is host to at least 1500 species native to that landscape and nowhere else.

Researchers at the time calculated that 44% of all vascular plants and 35% of all amphibians, reptiles, birds and mammals could be concentrated in just 25 such hotspots on the world’s continents and islands.

The hotspot count has since been increased to 34. But the message has remained. Focus on preserving and protecting these areas and you have a “silver bullet” strategy for conserving wildlife worldwide.

First such inventory

But, say scientists in the journal Frontiers in Ecology and the Environment, between 1992 and 2015 much of this precious wilderness has been consumed by agriculture, or paved by sprawling cities.

Their analysis of high resolution land-cover maps made by the European Space Agency is the first to try to look at the global inventory of hotspots, over a time frame of almost a quarter century.

“We see that not even focusing protection on a small range of areas worked well,” said Francesco Cherubini of the Norwegian University of Science and Technology, who with colleagues carried out the research. “There was major deforestation even in areas that were supposed to be protected.”

Two fifths of the lost landscapes were in forests, and agriculture accounted for most of this loss, particularly in the tropical forests of Indonesia, the Indo-Burma region and Mesoamerica. Five per cent of the lost hotspots were in areas formally declared as under state protection.

“The soils in these areas are very fertile, and agricultural yields can be very high. So it’s very productive land from an agricultural point of view, and attractive to farmers and local authorities that have to think about rising local incomes by feeding a growing population,” Professor Cherubini said.

“Not even focusing protection on a small range of areas worked well … There was major deforestation even in areas that were supposed to be protected.”

But most of the lost land went not to feeding people: it went instead to producing palm oil or soybeans for cattle feed. And local people may not have benefited: the change was driven by commercial agribusiness.

“You have these big companies that are making these investments, with high risks of land overexploitation and environmental degradation. The local population might get some benefits from revenues, but not much.”

The tension between hungry humans and vulnerable wilderness continues. Once again, such research supports a call for the people of the planet to consider a switch to plant-based diets, a switch that could contain climate change and preserve the natural capital on which all life depends. But many of those rich habitats are in some of the poorest countries.

“We need to be able somehow to link protection to poverty alleviation, because most of the biodiversity hotspots are in underdeveloped countries and it’s difficult to go there and say to a farmer, ‘Well, you need to keep this forest − don’t have a rice paddy or a field to feed your family’”, Professor Cherubini said.

“We need to also make it possible for the local communities to benefit from protection measures. They need income, too.” − Climate News Network

Stockholm heat toll 'doubled in 30 years'

FOR IMMEDIATE RELEASE
Swedish researchers think the changing climate was responsible for doubling the number of heat-related deaths in the capital, Stockholm, in the 30 years from 1980.

LONDON, 23 October – It’s a small sample – just one city, during one 30-year interval – but it could have significance everywhere: deaths from extreme heat doubled in Stockholm, Sweden, between 1980 and 2009 and the agent behind this grim reckoning looks very much like global warming.

Daniel Oudin Åström of Umeå University, Sweden, and colleagues, report in Nature Climate Change that they looked at recent mortality in Stockholm, and then compared the records of deaths with those from 1900-1929.  The period 1980-2009 was marked by northern hemisphere summers with unprecedented extremes of heat – in 2003, 2007, 2010 and 2012 – and in 2010, temperatures in Europe exceeded all 20th and 21st century records.

Stockholm is a city more adapted to cold than heat, more associated with long bleak winters than stifling summers. Sweden is a society with a long history of good record-keeping, but Stockholm in particular is also a city of demographic change and immigration. So the population at risk from extremes of heat in this century cannot be matched very easily with that of a century ago, but Åström and his fellow researchers decided it was worth a try.

They calculated the weeks in which people would have been most at risk – from cold in winter as well as heat in summer – and considered the age groups most likely to suffer and collapse from heat exhaustion and heat stroke or from hypothermia and other winter hazards. They counted 220 extremes of cold at the beginning of the 20th century, and 251 such extremes in the last 30 years. Then they compared the pattern of mortality over the two timespans, and concluded that the extra 31 cold spells accounted for 75 premature deaths.

Then they looked at the high end of the thermometer, and saw a much more dramatic change. In the early 20th century, there were 220 very hot spells. In the most recent period, there were 381 extremes of heat. On this basis, an additional 288 people who died in Stockholm from the effects of heat did so with a 95% probability that climate change was implicated.

Determining the cause

Comparisons like these are very difficult to make. Human life expectancy has increased, and so has overall health care, sanitation and education.  Cities have expanded dramatically in the last 100 years. Motor traffic, street lighting, central heating and air conditioning have all helped make air temperatures in cities so much higher than in the surrounding countryside, where comparative meteorological measurements are normally made.

The Swedish scientists took such changes into account: without such adjustments, their extra death toll would have been 447.  They concluded that heat-related deaths in the last 30 years were twice those to be expected in the period before global warming.

Despite overall warming, and higher than average winter temperatures overall, the frequency of extremes of cold had increased during the same period, with a smaller excess of deaths. And the researchers confirm that they found no evidence that humans had physiologically adapted to a warmer world in the years since global temperatures began to rise.

Scientists make such calculations and then publish them, inviting other researchers to pour cold water on them. In fact, the cold water is coming anyway, according to Andrea Toreti of Justus Liebig University Giessen in Germany and colleagues.

They report in Geophysical Research Letters that as the atmosphere warms, so the air will be able to hold more water vapour, with all the more to fall on rainy days. The researchers took eight high resolution global general circulation models and tried to calculate rainfall extremes for the remainder of the century.

To do that, they took reliable data from the past, and projected the pattern of extremes to 2099. They also divided their projections into three time periods: from 1966 to 2005; from 2020 to 2059; and from 2060 to 2099.

The not very surprising conclusion is that with increasing temperatures, and with more moisture in the air, there will be more rain. But the scientists were looking for extreme events, and conclude that as the century wears on, extreme torrential downpours of the kind that once happened only every 50 years will start to happen every 20 years or so.

In the high latitude northern hemisphere (and that includes Stockholm) the strongest change will be in autumn and spring, where the daily extreme precipitation is expected to increase by 45% and 39% respectively. – Climate News Network

FOR IMMEDIATE RELEASE
Swedish researchers think the changing climate was responsible for doubling the number of heat-related deaths in the capital, Stockholm, in the 30 years from 1980.

LONDON, 23 October – It’s a small sample – just one city, during one 30-year interval – but it could have significance everywhere: deaths from extreme heat doubled in Stockholm, Sweden, between 1980 and 2009 and the agent behind this grim reckoning looks very much like global warming.

Daniel Oudin Åström of Umeå University, Sweden, and colleagues, report in Nature Climate Change that they looked at recent mortality in Stockholm, and then compared the records of deaths with those from 1900-1929.  The period 1980-2009 was marked by northern hemisphere summers with unprecedented extremes of heat – in 2003, 2007, 2010 and 2012 – and in 2010, temperatures in Europe exceeded all 20th and 21st century records.

Stockholm is a city more adapted to cold than heat, more associated with long bleak winters than stifling summers. Sweden is a society with a long history of good record-keeping, but Stockholm in particular is also a city of demographic change and immigration. So the population at risk from extremes of heat in this century cannot be matched very easily with that of a century ago, but Åström and his fellow researchers decided it was worth a try.

They calculated the weeks in which people would have been most at risk – from cold in winter as well as heat in summer – and considered the age groups most likely to suffer and collapse from heat exhaustion and heat stroke or from hypothermia and other winter hazards. They counted 220 extremes of cold at the beginning of the 20th century, and 251 such extremes in the last 30 years. Then they compared the pattern of mortality over the two timespans, and concluded that the extra 31 cold spells accounted for 75 premature deaths.

Then they looked at the high end of the thermometer, and saw a much more dramatic change. In the early 20th century, there were 220 very hot spells. In the most recent period, there were 381 extremes of heat. On this basis, an additional 288 people who died in Stockholm from the effects of heat did so with a 95% probability that climate change was implicated.

Determining the cause

Comparisons like these are very difficult to make. Human life expectancy has increased, and so has overall health care, sanitation and education.  Cities have expanded dramatically in the last 100 years. Motor traffic, street lighting, central heating and air conditioning have all helped make air temperatures in cities so much higher than in the surrounding countryside, where comparative meteorological measurements are normally made.

The Swedish scientists took such changes into account: without such adjustments, their extra death toll would have been 447.  They concluded that heat-related deaths in the last 30 years were twice those to be expected in the period before global warming.

Despite overall warming, and higher than average winter temperatures overall, the frequency of extremes of cold had increased during the same period, with a smaller excess of deaths. And the researchers confirm that they found no evidence that humans had physiologically adapted to a warmer world in the years since global temperatures began to rise.

Scientists make such calculations and then publish them, inviting other researchers to pour cold water on them. In fact, the cold water is coming anyway, according to Andrea Toreti of Justus Liebig University Giessen in Germany and colleagues.

They report in Geophysical Research Letters that as the atmosphere warms, so the air will be able to hold more water vapour, with all the more to fall on rainy days. The researchers took eight high resolution global general circulation models and tried to calculate rainfall extremes for the remainder of the century.

To do that, they took reliable data from the past, and projected the pattern of extremes to 2099. They also divided their projections into three time periods: from 1966 to 2005; from 2020 to 2059; and from 2060 to 2099.

The not very surprising conclusion is that with increasing temperatures, and with more moisture in the air, there will be more rain. But the scientists were looking for extreme events, and conclude that as the century wears on, extreme torrential downpours of the kind that once happened only every 50 years will start to happen every 20 years or so.

In the high latitude northern hemisphere (and that includes Stockholm) the strongest change will be in autumn and spring, where the daily extreme precipitation is expected to increase by 45% and 39% respectively. – Climate News Network

Stockholm heat toll ‘doubled in 30 years’

FOR IMMEDIATE RELEASE Swedish researchers think the changing climate was responsible for doubling the number of heat-related deaths in the capital, Stockholm, in the 30 years from 1980. LONDON, 23 October – It’s a small sample – just one city, during one 30-year interval – but it could have significance everywhere: deaths from extreme heat doubled in Stockholm, Sweden, between 1980 and 2009 and the agent behind this grim reckoning looks very much like global warming. Daniel Oudin Åström of Umeå University, Sweden, and colleagues, report in Nature Climate Change that they looked at recent mortality in Stockholm, and then compared the records of deaths with those from 1900-1929.  The period 1980-2009 was marked by northern hemisphere summers with unprecedented extremes of heat – in 2003, 2007, 2010 and 2012 – and in 2010, temperatures in Europe exceeded all 20th and 21st century records. Stockholm is a city more adapted to cold than heat, more associated with long bleak winters than stifling summers. Sweden is a society with a long history of good record-keeping, but Stockholm in particular is also a city of demographic change and immigration. So the population at risk from extremes of heat in this century cannot be matched very easily with that of a century ago, but Åström and his fellow researchers decided it was worth a try. They calculated the weeks in which people would have been most at risk – from cold in winter as well as heat in summer – and considered the age groups most likely to suffer and collapse from heat exhaustion and heat stroke or from hypothermia and other winter hazards. They counted 220 extremes of cold at the beginning of the 20th century, and 251 such extremes in the last 30 years. Then they compared the pattern of mortality over the two timespans, and concluded that the extra 31 cold spells accounted for 75 premature deaths. Then they looked at the high end of the thermometer, and saw a much more dramatic change. In the early 20th century, there were 220 very hot spells. In the most recent period, there were 381 extremes of heat. On this basis, an additional 288 people who died in Stockholm from the effects of heat did so with a 95% probability that climate change was implicated.

Determining the cause

Comparisons like these are very difficult to make. Human life expectancy has increased, and so has overall health care, sanitation and education.  Cities have expanded dramatically in the last 100 years. Motor traffic, street lighting, central heating and air conditioning have all helped make air temperatures in cities so much higher than in the surrounding countryside, where comparative meteorological measurements are normally made. The Swedish scientists took such changes into account: without such adjustments, their extra death toll would have been 447.  They concluded that heat-related deaths in the last 30 years were twice those to be expected in the period before global warming. Despite overall warming, and higher than average winter temperatures overall, the frequency of extremes of cold had increased during the same period, with a smaller excess of deaths. And the researchers confirm that they found no evidence that humans had physiologically adapted to a warmer world in the years since global temperatures began to rise. Scientists make such calculations and then publish them, inviting other researchers to pour cold water on them. In fact, the cold water is coming anyway, according to Andrea Toreti of Justus Liebig University Giessen in Germany and colleagues. They report in Geophysical Research Letters that as the atmosphere warms, so the air will be able to hold more water vapour, with all the more to fall on rainy days. The researchers took eight high resolution global general circulation models and tried to calculate rainfall extremes for the remainder of the century. To do that, they took reliable data from the past, and projected the pattern of extremes to 2099. They also divided their projections into three time periods: from 1966 to 2005; from 2020 to 2059; and from 2060 to 2099. The not very surprising conclusion is that with increasing temperatures, and with more moisture in the air, there will be more rain. But the scientists were looking for extreme events, and conclude that as the century wears on, extreme torrential downpours of the kind that once happened only every 50 years will start to happen every 20 years or so. In the high latitude northern hemisphere (and that includes Stockholm) the strongest change will be in autumn and spring, where the daily extreme precipitation is expected to increase by 45% and 39% respectively. – Climate News Network

FOR IMMEDIATE RELEASE Swedish researchers think the changing climate was responsible for doubling the number of heat-related deaths in the capital, Stockholm, in the 30 years from 1980. LONDON, 23 October – It’s a small sample – just one city, during one 30-year interval – but it could have significance everywhere: deaths from extreme heat doubled in Stockholm, Sweden, between 1980 and 2009 and the agent behind this grim reckoning looks very much like global warming. Daniel Oudin Åström of Umeå University, Sweden, and colleagues, report in Nature Climate Change that they looked at recent mortality in Stockholm, and then compared the records of deaths with those from 1900-1929.  The period 1980-2009 was marked by northern hemisphere summers with unprecedented extremes of heat – in 2003, 2007, 2010 and 2012 – and in 2010, temperatures in Europe exceeded all 20th and 21st century records. Stockholm is a city more adapted to cold than heat, more associated with long bleak winters than stifling summers. Sweden is a society with a long history of good record-keeping, but Stockholm in particular is also a city of demographic change and immigration. So the population at risk from extremes of heat in this century cannot be matched very easily with that of a century ago, but Åström and his fellow researchers decided it was worth a try. They calculated the weeks in which people would have been most at risk – from cold in winter as well as heat in summer – and considered the age groups most likely to suffer and collapse from heat exhaustion and heat stroke or from hypothermia and other winter hazards. They counted 220 extremes of cold at the beginning of the 20th century, and 251 such extremes in the last 30 years. Then they compared the pattern of mortality over the two timespans, and concluded that the extra 31 cold spells accounted for 75 premature deaths. Then they looked at the high end of the thermometer, and saw a much more dramatic change. In the early 20th century, there were 220 very hot spells. In the most recent period, there were 381 extremes of heat. On this basis, an additional 288 people who died in Stockholm from the effects of heat did so with a 95% probability that climate change was implicated.

Determining the cause

Comparisons like these are very difficult to make. Human life expectancy has increased, and so has overall health care, sanitation and education.  Cities have expanded dramatically in the last 100 years. Motor traffic, street lighting, central heating and air conditioning have all helped make air temperatures in cities so much higher than in the surrounding countryside, where comparative meteorological measurements are normally made. The Swedish scientists took such changes into account: without such adjustments, their extra death toll would have been 447.  They concluded that heat-related deaths in the last 30 years were twice those to be expected in the period before global warming. Despite overall warming, and higher than average winter temperatures overall, the frequency of extremes of cold had increased during the same period, with a smaller excess of deaths. And the researchers confirm that they found no evidence that humans had physiologically adapted to a warmer world in the years since global temperatures began to rise. Scientists make such calculations and then publish them, inviting other researchers to pour cold water on them. In fact, the cold water is coming anyway, according to Andrea Toreti of Justus Liebig University Giessen in Germany and colleagues. They report in Geophysical Research Letters that as the atmosphere warms, so the air will be able to hold more water vapour, with all the more to fall on rainy days. The researchers took eight high resolution global general circulation models and tried to calculate rainfall extremes for the remainder of the century. To do that, they took reliable data from the past, and projected the pattern of extremes to 2099. They also divided their projections into three time periods: from 1966 to 2005; from 2020 to 2059; and from 2060 to 2099. The not very surprising conclusion is that with increasing temperatures, and with more moisture in the air, there will be more rain. But the scientists were looking for extreme events, and conclude that as the century wears on, extreme torrential downpours of the kind that once happened only every 50 years will start to happen every 20 years or so. In the high latitude northern hemisphere (and that includes Stockholm) the strongest change will be in autumn and spring, where the daily extreme precipitation is expected to increase by 45% and 39% respectively. – Climate News Network