Tag Archives: plant growth

Cattle weight loss means slimmer profits

FOR IMMEDIATE RELEASE A study of bison in the US predicts that wild and domestic cattle will drastically reduce in weight as the climate warms − compromising food security and stripping billions of dollars from farm profits LONDON, June 29 − America’s cattle herds will shrink – not in number, but in weight and yield – as the climate warms, according to new research that delivers an ominous warning for farmers. An extensive study of bison − those great wild cattle that evolved to graze the prairies of North America − has confirmed that animals from warmer, drier grasslands weigh considerably less on average than those from cool, wet ranges. Joseph Craine, a researcher from Kansas State University’s Division of Biology, reports in the Public Library of Science journal PloS One that he analysed weight, age and sex data from 290,000 animals in 22 herds throughout the US. He found that the average seven-year-old male bison in South Dakota weighed 856kg (around 1900lbs), while counterparts in Oklahoma clocked in at 596kg (1300lbs).

Ominous change

The difference in mean annual temperature between the two ranges was 11°C, and the two sets of values told an ominous story of change in a warming world − not just for wild bison, but also for domestic cattle. The world is almost certain to warm by more than 2°C on average in this century, and the rise could be as great at 4°C. “We know that temperatures are going to go up,” Dr Craine says. “We also know that warmer grasslands have grasses with less protein, and we now know that warmer grasslands have smaller grazers. It all lines up to suggest that climate change will cause grasses to have less protein, and cause grazers to gain less weight in future.” As temperatures rise, precipitation is likely to fall, with consequences for plant growth. If the same reduction in weight gain applies to beef cattle as to bison, the finding is “a pretty clear indication” of bad news for food security and for the graziers. There are around 500,000 bison in the US – the species was all but extinguished during the 19th century – and more than 90 million cattle. Dr Craine calculates that each 1°C rise in average temperatures could cost farmers $1 billion in profits, either through direct reduction in weight gains or in the costs of additional supplementary feeds.

Dwindling size

The research is in line with other findings this year. Climate News Network reported in January that evidence from 55 million years ago − when the world warmed by 6°C – was unearthed during drilling in the National Science Foundation’s Bighorn Basin Coring Project in Wyoming. It indicated that animal size tended to dwindle with rising temperatures, almost certainly in response to changes in nutritional value. The implication that mammals could dwarf and humans shrink towards hobbit-like stature under a changing climate was tragically confirmed by a study of body heights among children in north-east Brazil, as Climate News Network reported in February this year . In response to near-starvation conditions, children who were brought up on a diet of rats, snakes and cacti reached an average adult size of only 1.35 metres (4ft 6ins). − Climate News Network

FOR IMMEDIATE RELEASE A study of bison in the US predicts that wild and domestic cattle will drastically reduce in weight as the climate warms − compromising food security and stripping billions of dollars from farm profits LONDON, June 29 − America’s cattle herds will shrink – not in number, but in weight and yield – as the climate warms, according to new research that delivers an ominous warning for farmers. An extensive study of bison − those great wild cattle that evolved to graze the prairies of North America − has confirmed that animals from warmer, drier grasslands weigh considerably less on average than those from cool, wet ranges. Joseph Craine, a researcher from Kansas State University’s Division of Biology, reports in the Public Library of Science journal PloS One that he analysed weight, age and sex data from 290,000 animals in 22 herds throughout the US. He found that the average seven-year-old male bison in South Dakota weighed 856kg (around 1900lbs), while counterparts in Oklahoma clocked in at 596kg (1300lbs).

Ominous change

The difference in mean annual temperature between the two ranges was 11°C, and the two sets of values told an ominous story of change in a warming world − not just for wild bison, but also for domestic cattle. The world is almost certain to warm by more than 2°C on average in this century, and the rise could be as great at 4°C. “We know that temperatures are going to go up,” Dr Craine says. “We also know that warmer grasslands have grasses with less protein, and we now know that warmer grasslands have smaller grazers. It all lines up to suggest that climate change will cause grasses to have less protein, and cause grazers to gain less weight in future.” As temperatures rise, precipitation is likely to fall, with consequences for plant growth. If the same reduction in weight gain applies to beef cattle as to bison, the finding is “a pretty clear indication” of bad news for food security and for the graziers. There are around 500,000 bison in the US – the species was all but extinguished during the 19th century – and more than 90 million cattle. Dr Craine calculates that each 1°C rise in average temperatures could cost farmers $1 billion in profits, either through direct reduction in weight gains or in the costs of additional supplementary feeds.

Dwindling size

The research is in line with other findings this year. Climate News Network reported in January that evidence from 55 million years ago − when the world warmed by 6°C – was unearthed during drilling in the National Science Foundation’s Bighorn Basin Coring Project in Wyoming. It indicated that animal size tended to dwindle with rising temperatures, almost certainly in response to changes in nutritional value. The implication that mammals could dwarf and humans shrink towards hobbit-like stature under a changing climate was tragically confirmed by a study of body heights among children in north-east Brazil, as Climate News Network reported in February this year . In response to near-starvation conditions, children who were brought up on a diet of rats, snakes and cacti reached an average adult size of only 1.35 metres (4ft 6ins). − Climate News Network

Plant Growth Surges As CO2 Levels Rise

New study predicts a big jump in foliage growth in arid regions as carbon dioxide levels increase  LONDON, 2 June – Australian scientists have solved one piece of the climate puzzle. They have confirmed the long-debated fertilization effect. Plants build their tissues by using photosynthesis to take carbon from the air around them. So more carbon dioxide should mean more vigorous plant growth – though until now this has been very difficult to prove. Randall Donohue of the Commonwealth Scientific and Industrial Organisation in Canberra, Australia, and his colleagues developed a mathematical model to predict the extent of this carbon dioxide fertilization effect. Between 1982 and 2010, carbon dioxide levels in the atmosphere increased by 14%. So, their model suggested, foliage worldwide should have increased by between 5 and 10%. Measuring uncertainties It is one thing to predict an effect, quite another to prove it. Satellite observations can and successfully do measure seasonal changes in vegetation, the growth of deserts, the change from open prairie to savannah, the growth of new trees in the tundra and so on, but it’s very difficult to be sure that these changes have anything to do with carbon dioxide fertilization: changes in temperature and rainfall patterns would also have an impact. Also, some regions – tropical rainforests, for example – are already completely covered by forest canopy: orbiting satellites are unlikely to measure much change there. Donohue and his team, in a study appearing in Geophysical Research Letters, the journal of the American Geophysical Union, looked at those regions where leaf cover really would stand out, and where carbon dioxide fertilization would be the best explanation for new growth. These were the warm, dry places: while the researchers focused on changes in arid regions in North America’s south-west, Australia’s Outback, the Middle East and parts of Africa, they also had to find a technique that allowed for natural seasonal and cyclic changes, alterations in land use and so on. They calculated that in these conditions, plants would make more leaves if they had the water to do so. “A leaf can extract more carbon from the air during photosynthesis, or lose less water to the air during photosynthesis, or both, due to elevated CO2,” says Donohue. That is the CO2 fertilization effect. Calculating greenness The team averaged the greenness of each location over three year periods, and then grouped the greenness data from different locations according to known records of rainfall. They also looked at variations in foliage over a 20 year period. In the end, they teased out the carbon dioxide fertilization effect from all other influences and calculated that this could account for an 11% increase in global foliage since 1982. This is what’s called negative feedback with at least some of the increasing levels of carbon dioxide being absorbed by extra plant growth. It could also be good news for biodiversity, and good news for food security: plants are the primary producers that feed all animals. Trees are likely to invade grasslands in the drier regions, and their deep roots are better equipped to tap groundwater and at the same time stabilise the soils. “Even if nothing else in the climate changes as global CO2 levels rise, we will still see significant environmental changes because of the CO2 fertilization effect,” says Dr Donohue. – Climate News Network

New study predicts a big jump in foliage growth in arid regions as carbon dioxide levels increase  LONDON, 2 June – Australian scientists have solved one piece of the climate puzzle. They have confirmed the long-debated fertilization effect. Plants build their tissues by using photosynthesis to take carbon from the air around them. So more carbon dioxide should mean more vigorous plant growth – though until now this has been very difficult to prove. Randall Donohue of the Commonwealth Scientific and Industrial Organisation in Canberra, Australia, and his colleagues developed a mathematical model to predict the extent of this carbon dioxide fertilization effect. Between 1982 and 2010, carbon dioxide levels in the atmosphere increased by 14%. So, their model suggested, foliage worldwide should have increased by between 5 and 10%. Measuring uncertainties It is one thing to predict an effect, quite another to prove it. Satellite observations can and successfully do measure seasonal changes in vegetation, the growth of deserts, the change from open prairie to savannah, the growth of new trees in the tundra and so on, but it’s very difficult to be sure that these changes have anything to do with carbon dioxide fertilization: changes in temperature and rainfall patterns would also have an impact. Also, some regions – tropical rainforests, for example – are already completely covered by forest canopy: orbiting satellites are unlikely to measure much change there. Donohue and his team, in a study appearing in Geophysical Research Letters, the journal of the American Geophysical Union, looked at those regions where leaf cover really would stand out, and where carbon dioxide fertilization would be the best explanation for new growth. These were the warm, dry places: while the researchers focused on changes in arid regions in North America’s south-west, Australia’s Outback, the Middle East and parts of Africa, they also had to find a technique that allowed for natural seasonal and cyclic changes, alterations in land use and so on. They calculated that in these conditions, plants would make more leaves if they had the water to do so. “A leaf can extract more carbon from the air during photosynthesis, or lose less water to the air during photosynthesis, or both, due to elevated CO2,” says Donohue. That is the CO2 fertilization effect. Calculating greenness The team averaged the greenness of each location over three year periods, and then grouped the greenness data from different locations according to known records of rainfall. They also looked at variations in foliage over a 20 year period. In the end, they teased out the carbon dioxide fertilization effect from all other influences and calculated that this could account for an 11% increase in global foliage since 1982. This is what’s called negative feedback with at least some of the increasing levels of carbon dioxide being absorbed by extra plant growth. It could also be good news for biodiversity, and good news for food security: plants are the primary producers that feed all animals. Trees are likely to invade grasslands in the drier regions, and their deep roots are better equipped to tap groundwater and at the same time stabilise the soils. “Even if nothing else in the climate changes as global CO2 levels rise, we will still see significant environmental changes because of the CO2 fertilization effect,” says Dr Donohue. – Climate News Network