climate changes
Climate Changes
Scanning the news for pointers as to where the world is headed is a fascinating game. Over the past few weeks several interesting reports on the environment have been published. Let me share some of them with you.
A new and comprehensive IUCN report Explaining Ocean Warming warns that Ocean warming may well turn out to be the greatest hidden challenge of our generation. As this report was being produced the world faced the 14th consecutive month of record-breaking global temperatures on land. In the ocean, 2015 was analysed to have been the warmest year within the 136-year records of extended reconstructed sea surface temperature and the fourth such record-breaking year since 2005. An analysis undertaken by the Grantham Institute in 2015 concluded that if the same amount of heat that has gone into the top 2000m of the ocean between 1955 and 2010 had gone into the lower 10km of the atmosphere, then the Earth would have seen a warming of 36°C. By factoring in the ocean, as this report shows, the perspective is fundamentally altered.
A multinational study launched to support a legal case brought by a group of young people against the US government entitled Young People’s Burden: Requirement of Negative CO2 Emissions records that the rapid rise of global temperature that began about 1975 continues at a mean rate of about 0.18°C / decade, with the current annual temperature exceeding 1.25°C relative to 1880-1920. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content. In this case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial could be limited and irreversible climate impacts could be minimized. However, continued high fossil fuel emissions by the current generation would place a burden on young people to undertake massive technological CO2 extraction if they are to limit climate change and imply minimal estimated costs of 104-570 trillion dollars this century, with large risks and uncertain feasibility.
The latest World Meteorological Organization Greenhouse Gas Bulletin shows that during a strong El Nino event, such as that which started in 2015, atmospheric CO2 levels rise as the earth is less able to absorb them. The latest analysis of observations from the WMO Global Atmosphere Watch Programme shows that globally averaged surface mole fractions calculated from this in situ network for carbon dioxide, methane and nitrous oxide reached new highs in 2015, with values, respectively, of 144%, 256% and 121% of pre-industrial (before 1750) levels. They predict that 2016 will be the first year in which CO2 at the Mauna Loa Observatory remains above 400 ppm all year.
An OECD working paper, the cost of air pollution in Africa, calculates that the death toll from air pollution in Africa has increased significantly from 1990 to 2013 in tandem with the uninterrupted growth in the size of the urban population of Africa. Premature deaths from air pollution now exceed those caused by unsafe water and sanitation.
The Australian Bureau of Meteorology and CSIRO have released their fourth biennial State of the Climate Report. Australia's climate has warmed in both mean surface air temperature and surrounding sea surface temperature by around 1 °C since 1910. The duration, frequency and intensity of extreme heat events have increased across large parts of Australia. Since 1970 May–July rainfall has reduced by around 19% in the southwest of Australia and increased across parts of northern Australia. There has been a decline of around 11% since the mid-1990s in the April–October growing season rainfall in the continental southeast. Oceans around Australia have warmed and ocean acidity levels have increased. Sea levels have risen around Australia.
An article in Science Magazine Climate change: The 2015 Paris Agreement thresholds and Mediterranean basin ecosystems forecasts that even if emissions are held to the level of pledges put forward ahead of the Paris agreement, southern Europe, particularly Spain and Sicily, would experience a “substantial” expansion of deserts.
Further north, research by the by the University of Neuchâtel along with the Federal institute for research on forests, snow and the countryside (WSL) and the Institute for the study of snow and avalanches (SLF) found that Switzerland has nearly 40 fewer snow days a season than it did in the 1970s. Overall, snow arrived 12 days later and disappeared 25 days earlier in 2015 than in 1970. The maximum snow depth also reduced by 25% over the years and the day on which this maximum is achieved arrives 28 days earlier now than 45 years ago.
In a recent Proceedings of the National Academy of Sciences, scientists from the University of Idaho and Columbia University calculated how much of the increased scope and intensity of Western wildfires can be attributed to human-caused climate change and its effects. Since 1979, climate change is responsible for more than half of the dryness of Western forests and the increased length of the fire season. Since 1984, those factors have enlarged the cumulative forest fire area by 16,000 square miles, about the size of Massachusetts and Connecticut combined. The pattern of longer fire seasons and more burned acres of forest is likely to continue as long as there is enough fuel to burn, but that there will come a point, probably in the middle of the century, when there are not enough trees left to sustain wildfires.
Another Proceeding’s study on a very different topic shows that the frequency of Hurricane Sandy-like extreme flood events has increased significantly over the past two centuries and is very likely to increase more sharply over the 21st century, due to the compound effects of sea level rise and storm climatology change.
A paper in Nature Geoscience titled Intensification of landfalling typhoons over the northwest Pacific since the late 1970s show that, over the past 37 years, typhoons that strike East and Southeast Asia have intensified by 12–15%, with the proportion of storms of categories 4 and 5 having doubled or even tripled. In contrast, typhoons that stay over the open ocean have experienced only modest changes. The increased intensity of landfalling typhoons is tied to locally enhanced ocean surface warming on the rim of East and Southeast Asia. The projected ocean surface warming pattern under increasing greenhouse gas forcing suggests that typhoons striking eastern mainland China, Taiwan, Korea and Japan will intensify further.
A paper in Science Advances titled Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet calculates that melting of the Greenland ice sheet has taken place faster than previously measured because the land mass is rising as the weight of the ice reduces.
Another paper in Science Advances titled Relative impacts of mitigation, temperature, and precipitation on 21st-century megadrought risk in the American Southwest predicts that there is a high probability that during the 21st century the US states of California, Nevada, New Mexico, Colorado and Utah could experience a megadrought lasting as long as 35 years.
Well, there’s plenty there to get heated about!!
Useful Links
The Australian Bureau of Meteorology and CSIRO State of the Climate Report is excellent.
IUCN report Explaining Ocean Warming
World Meteorological Organization Greenhouse Gas Bulletin
OECD working paper, the cost of air pollution in Africa
Swiss Snow Melt
Science Advances titled Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet
Science Advances titled Relative impacts of mitigation, temperature, and precipitation on 21st-century megadrought risk in the American Southwest
Young People’s Burden: Requirement of Negative CO2 Emissions
Proceedings of the National Academy of Sciences
Scanning the news for pointers as to where the world is headed is a fascinating game. Over the past few weeks several interesting reports on the environment have been published. Let me share some of them with you.
A new and comprehensive IUCN report Explaining Ocean Warming warns that Ocean warming may well turn out to be the greatest hidden challenge of our generation. As this report was being produced the world faced the 14th consecutive month of record-breaking global temperatures on land. In the ocean, 2015 was analysed to have been the warmest year within the 136-year records of extended reconstructed sea surface temperature and the fourth such record-breaking year since 2005. An analysis undertaken by the Grantham Institute in 2015 concluded that if the same amount of heat that has gone into the top 2000m of the ocean between 1955 and 2010 had gone into the lower 10km of the atmosphere, then the Earth would have seen a warming of 36°C. By factoring in the ocean, as this report shows, the perspective is fundamentally altered.
A multinational study launched to support a legal case brought by a group of young people against the US government entitled Young People’s Burden: Requirement of Negative CO2 Emissions records that the rapid rise of global temperature that began about 1975 continues at a mean rate of about 0.18°C / decade, with the current annual temperature exceeding 1.25°C relative to 1880-1920. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content. In this case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial could be limited and irreversible climate impacts could be minimized. However, continued high fossil fuel emissions by the current generation would place a burden on young people to undertake massive technological CO2 extraction if they are to limit climate change and imply minimal estimated costs of 104-570 trillion dollars this century, with large risks and uncertain feasibility.
The latest World Meteorological Organization Greenhouse Gas Bulletin shows that during a strong El Nino event, such as that which started in 2015, atmospheric CO2 levels rise as the earth is less able to absorb them. The latest analysis of observations from the WMO Global Atmosphere Watch Programme shows that globally averaged surface mole fractions calculated from this in situ network for carbon dioxide, methane and nitrous oxide reached new highs in 2015, with values, respectively, of 144%, 256% and 121% of pre-industrial (before 1750) levels. They predict that 2016 will be the first year in which CO2 at the Mauna Loa Observatory remains above 400 ppm all year.
An OECD working paper, the cost of air pollution in Africa, calculates that the death toll from air pollution in Africa has increased significantly from 1990 to 2013 in tandem with the uninterrupted growth in the size of the urban population of Africa. Premature deaths from air pollution now exceed those caused by unsafe water and sanitation.
The Australian Bureau of Meteorology and CSIRO have released their fourth biennial State of the Climate Report. Australia's climate has warmed in both mean surface air temperature and surrounding sea surface temperature by around 1 °C since 1910. The duration, frequency and intensity of extreme heat events have increased across large parts of Australia. Since 1970 May–July rainfall has reduced by around 19% in the southwest of Australia and increased across parts of northern Australia. There has been a decline of around 11% since the mid-1990s in the April–October growing season rainfall in the continental southeast. Oceans around Australia have warmed and ocean acidity levels have increased. Sea levels have risen around Australia.
An article in Science Magazine Climate change: The 2015 Paris Agreement thresholds and Mediterranean basin ecosystems forecasts that even if emissions are held to the level of pledges put forward ahead of the Paris agreement, southern Europe, particularly Spain and Sicily, would experience a “substantial” expansion of deserts.
Further north, research by the by the University of Neuchâtel along with the Federal institute for research on forests, snow and the countryside (WSL) and the Institute for the study of snow and avalanches (SLF) found that Switzerland has nearly 40 fewer snow days a season than it did in the 1970s. Overall, snow arrived 12 days later and disappeared 25 days earlier in 2015 than in 1970. The maximum snow depth also reduced by 25% over the years and the day on which this maximum is achieved arrives 28 days earlier now than 45 years ago.
In a recent Proceedings of the National Academy of Sciences, scientists from the University of Idaho and Columbia University calculated how much of the increased scope and intensity of Western wildfires can be attributed to human-caused climate change and its effects. Since 1979, climate change is responsible for more than half of the dryness of Western forests and the increased length of the fire season. Since 1984, those factors have enlarged the cumulative forest fire area by 16,000 square miles, about the size of Massachusetts and Connecticut combined. The pattern of longer fire seasons and more burned acres of forest is likely to continue as long as there is enough fuel to burn, but that there will come a point, probably in the middle of the century, when there are not enough trees left to sustain wildfires.
Another Proceeding’s study on a very different topic shows that the frequency of Hurricane Sandy-like extreme flood events has increased significantly over the past two centuries and is very likely to increase more sharply over the 21st century, due to the compound effects of sea level rise and storm climatology change.
A paper in Nature Geoscience titled Intensification of landfalling typhoons over the northwest Pacific since the late 1970s show that, over the past 37 years, typhoons that strike East and Southeast Asia have intensified by 12–15%, with the proportion of storms of categories 4 and 5 having doubled or even tripled. In contrast, typhoons that stay over the open ocean have experienced only modest changes. The increased intensity of landfalling typhoons is tied to locally enhanced ocean surface warming on the rim of East and Southeast Asia. The projected ocean surface warming pattern under increasing greenhouse gas forcing suggests that typhoons striking eastern mainland China, Taiwan, Korea and Japan will intensify further.
A paper in Science Advances titled Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet calculates that melting of the Greenland ice sheet has taken place faster than previously measured because the land mass is rising as the weight of the ice reduces.
Another paper in Science Advances titled Relative impacts of mitigation, temperature, and precipitation on 21st-century megadrought risk in the American Southwest predicts that there is a high probability that during the 21st century the US states of California, Nevada, New Mexico, Colorado and Utah could experience a megadrought lasting as long as 35 years.
Well, there’s plenty there to get heated about!!
Useful Links
The Australian Bureau of Meteorology and CSIRO State of the Climate Report is excellent.
IUCN report Explaining Ocean Warming
World Meteorological Organization Greenhouse Gas Bulletin
OECD working paper, the cost of air pollution in Africa
Swiss Snow Melt
Science Advances titled Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet
Science Advances titled Relative impacts of mitigation, temperature, and precipitation on 21st-century megadrought risk in the American Southwest
Young People’s Burden: Requirement of Negative CO2 Emissions
Proceedings of the National Academy of Sciences
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