Tag Archives: Pests

Half of plants may move in warmer world

FOR IMMEDIATE RELEASE An international team of scientists says that by the end of the century one probable consequence of climate change will be a change in patterns of vegetation over much of the planet’s land surface. LONDON, 16 February – By 2100, vegetation patterns will be shifting in almost half the land area of the planet, according to new research in the journal Global and Planetary Change. Song Feng of the University of Arkansas in the US and colleagues in Nebraska, China and South Korea have taken a long cool look at what the projected patterns of warming are likely to do to the planet’s mosaic of climate types. And they predict dramatic changes. Climate type is a century-old idea useful for making sense of geographical zones: regions are grouped according to the type of vegetation they support. Since a global map of native vegetation types can also deliver useful information about altitude, rainfall, soil type, prevailing weather and latitude, geographers regard the Köppen-Geiger classification – and an updated version known as Köppen-Trewartha – as a helpful way of describing the world. Feng and his colleagues decided to see what projected changes in temperature would do to climate types. He wasn’t the first to do so; scientists from the US National Oceanic and Atmospheric Administration reported in 2013 in Nature Climate Change on the probable speed of change in such zones. But science advances by challenge and replication, and the Arkansas team began looking for themselves at the details of simulated change under the notorious “business as usual scenario”  – the one in which global fossil fuel use continues to increase and higher levels of carbon dioxide and other greenhouse gases concentrate in the atmosphere. The Intergovernmental Panel on Climate Change has made a series of predictions of rising global average temperatures, but plants, of course, don’t care about global average temperatures: they are however distinctly vulnerable to local extremes of frost and heat. The Feng scenario projected an increase of between 3°C and 10°C; the team analysed observations made between 1900 and 2010, and then ran computer simulations from 1900 to 2100.

Drastic changes ahead

In the last three decades of the 21st century, for instance, northern winter temperatures are likely to rise by between 3° and 12°C; Arctic coastal temperatures are likely to rise by 8°C; warming in mid-latitudes is likely to be between 5°C and 7°C, the tropics and the southern hemisphere around 5°C. The Arctic will shrink. Sub-polar vegetation is expected to advance by 5° of latitude and the temperate zones will push northwards too. Arid and semi-arid climate zones are expected to expand by somewhere between 3.3 and 6.6 million square kilometers in the last three decades of this century. What this does to native vegetation types is hard to predict in detail but some projections have been made. In the Qinling mountain region of China, for instance, somewhere between 80% and 100% of the bamboo forests on which the giant pandas depend could disappear, because the rising temperature would be “no longer feasible for bamboo growth.” In the south-western US higher temperatures and drier conditions could lead to more forest fires, and pest outbreaks could lead to changes in forest structure and composition. As the plants change, the animal species that evolved with the vegetation types could be increasingly at risk. Altogether, up to 46.3% of the planet’s land area could shift to warmer or drier climate types “Climates are associated with certain types of vegetation. If the surface continues to get warmer, certain native species may no longer grow well in their climate, especially in higher latitudes. They will give their territory to other species. That is the most likely scenario”, said Feng. – Climate News Network

FOR IMMEDIATE RELEASE An international team of scientists says that by the end of the century one probable consequence of climate change will be a change in patterns of vegetation over much of the planet’s land surface. LONDON, 16 February – By 2100, vegetation patterns will be shifting in almost half the land area of the planet, according to new research in the journal Global and Planetary Change. Song Feng of the University of Arkansas in the US and colleagues in Nebraska, China and South Korea have taken a long cool look at what the projected patterns of warming are likely to do to the planet’s mosaic of climate types. And they predict dramatic changes. Climate type is a century-old idea useful for making sense of geographical zones: regions are grouped according to the type of vegetation they support. Since a global map of native vegetation types can also deliver useful information about altitude, rainfall, soil type, prevailing weather and latitude, geographers regard the Köppen-Geiger classification – and an updated version known as Köppen-Trewartha – as a helpful way of describing the world. Feng and his colleagues decided to see what projected changes in temperature would do to climate types. He wasn’t the first to do so; scientists from the US National Oceanic and Atmospheric Administration reported in 2013 in Nature Climate Change on the probable speed of change in such zones. But science advances by challenge and replication, and the Arkansas team began looking for themselves at the details of simulated change under the notorious “business as usual scenario”  – the one in which global fossil fuel use continues to increase and higher levels of carbon dioxide and other greenhouse gases concentrate in the atmosphere. The Intergovernmental Panel on Climate Change has made a series of predictions of rising global average temperatures, but plants, of course, don’t care about global average temperatures: they are however distinctly vulnerable to local extremes of frost and heat. The Feng scenario projected an increase of between 3°C and 10°C; the team analysed observations made between 1900 and 2010, and then ran computer simulations from 1900 to 2100.

Drastic changes ahead

In the last three decades of the 21st century, for instance, northern winter temperatures are likely to rise by between 3° and 12°C; Arctic coastal temperatures are likely to rise by 8°C; warming in mid-latitudes is likely to be between 5°C and 7°C, the tropics and the southern hemisphere around 5°C. The Arctic will shrink. Sub-polar vegetation is expected to advance by 5° of latitude and the temperate zones will push northwards too. Arid and semi-arid climate zones are expected to expand by somewhere between 3.3 and 6.6 million square kilometers in the last three decades of this century. What this does to native vegetation types is hard to predict in detail but some projections have been made. In the Qinling mountain region of China, for instance, somewhere between 80% and 100% of the bamboo forests on which the giant pandas depend could disappear, because the rising temperature would be “no longer feasible for bamboo growth.” In the south-western US higher temperatures and drier conditions could lead to more forest fires, and pest outbreaks could lead to changes in forest structure and composition. As the plants change, the animal species that evolved with the vegetation types could be increasingly at risk. Altogether, up to 46.3% of the planet’s land area could shift to warmer or drier climate types “Climates are associated with certain types of vegetation. If the surface continues to get warmer, certain native species may no longer grow well in their climate, especially in higher latitudes. They will give their territory to other species. That is the most likely scenario”, said Feng. – Climate News Network

Crop pests head polewards to flee heat

EMBARGOED until 1700 GMT on Sunday 1 September Organisms which can threaten food and other crops are moving towards the poles to escape increasing heat where they live at present. That may be serious for the highest-yielding producers. LONDON, 1 September – A fungus is heading your way. The caterpillars are on the march.  So are viruses and any number of insects and nematode worms, and since 1960 they have been shifting north and south at an average speed of 3 kilometres a year as the world warms, according to researchers at Exeter University in the UK. Sandra Gurr and colleagues report in Nature Climate Change that they looked at more than 26,000 observations of 612 well-known crop pests and had access to observations made much earlier, including the first record of fungus attack on oilseed rape in the UK in 1822. Crop pests can cause famine, devastation and economic ruin. The 19th century Irish potato famine was caused by the pathogen Phytophthora infestans and the Great Bengal Famine of 1943 was blamed on the fungus Helminthosporium oryzae. And French winegrowers have never forgotten or forgiven the Phylloxera aphid that destroyed the vineyards. But losses to crop pests are a quiet disaster now: they routinely destroy between 10% and 16% of all crops – a lost harvest that would otherwise feed more than 8% of the planet’s people. And, warn Gurr and her co-authors, crop pests are still a threat to food security. The spread of pests towards the poles is certainly helped by human activity and they believe the most effective agency is international freight transport. But global warming is certainly making it a little easier every year for the pests to find a comfortable home and easy pickings in previously unsuitable regions.

Growing risk of loss

The mountain pine beetle Dendroctonus ponderosae has destroyed large areas of pine forest in the US Pacific Northwest. Rice blast fungus has now reached 80 countries, has had a dramatic effect on agricultural economies and on local ecosystems, and – ominously – has evolved to develop a taste for wheat. Wheat blast is now a big problem in Brazil. One reason for concern is that countries at higher latitudes – essentially, the developed world – are better able to monitor and manage emerging pests and diseases. But these are also the countries with the highest yields per hectare. If climate change makes it easier for crop diseases to spread, then there must be even more effort to watch out for new infestations and to control the spread of diseases. There is simply more to lose. “Renewed efforts are required to monitor the spread of crop pests and to control their movement from region to region if we are to halt the relentless destruction of crops across the world in the face of climate change”, says Professor Gurr. Her colleague Dan Bebber says: “If crop pests continue to march polewards as the Earth warms the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security.” – Climate News Network

EMBARGOED until 1700 GMT on Sunday 1 September Organisms which can threaten food and other crops are moving towards the poles to escape increasing heat where they live at present. That may be serious for the highest-yielding producers. LONDON, 1 September – A fungus is heading your way. The caterpillars are on the march.  So are viruses and any number of insects and nematode worms, and since 1960 they have been shifting north and south at an average speed of 3 kilometres a year as the world warms, according to researchers at Exeter University in the UK. Sandra Gurr and colleagues report in Nature Climate Change that they looked at more than 26,000 observations of 612 well-known crop pests and had access to observations made much earlier, including the first record of fungus attack on oilseed rape in the UK in 1822. Crop pests can cause famine, devastation and economic ruin. The 19th century Irish potato famine was caused by the pathogen Phytophthora infestans and the Great Bengal Famine of 1943 was blamed on the fungus Helminthosporium oryzae. And French winegrowers have never forgotten or forgiven the Phylloxera aphid that destroyed the vineyards. But losses to crop pests are a quiet disaster now: they routinely destroy between 10% and 16% of all crops – a lost harvest that would otherwise feed more than 8% of the planet’s people. And, warn Gurr and her co-authors, crop pests are still a threat to food security. The spread of pests towards the poles is certainly helped by human activity and they believe the most effective agency is international freight transport. But global warming is certainly making it a little easier every year for the pests to find a comfortable home and easy pickings in previously unsuitable regions.

Growing risk of loss

The mountain pine beetle Dendroctonus ponderosae has destroyed large areas of pine forest in the US Pacific Northwest. Rice blast fungus has now reached 80 countries, has had a dramatic effect on agricultural economies and on local ecosystems, and – ominously – has evolved to develop a taste for wheat. Wheat blast is now a big problem in Brazil. One reason for concern is that countries at higher latitudes – essentially, the developed world – are better able to monitor and manage emerging pests and diseases. But these are also the countries with the highest yields per hectare. If climate change makes it easier for crop diseases to spread, then there must be even more effort to watch out for new infestations and to control the spread of diseases. There is simply more to lose. “Renewed efforts are required to monitor the spread of crop pests and to control their movement from region to region if we are to halt the relentless destruction of crops across the world in the face of climate change”, says Professor Gurr. Her colleague Dan Bebber says: “If crop pests continue to march polewards as the Earth warms the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security.” – Climate News Network