Posted on May\u00a025,\u00a02013<\/h4>\n\n<\/p>\nBy Alex Kirby, Climate News Network<\/b><\/p>\n
This piece first appeared at Climate News Network<\/a>.<\/i><\/p>\nLONDON\u2013Several leading authorities on climate change have given a guarded welcome to research suggesting the Earth may warm more slowly than scientists had expected.<\/p>\n
An international research team led by Dr Alexander Otto of the Environmental Change Institute<\/a> (ECI) at the University of Oxford, UK, has reported its conclusions in the journal Nature Geoscience<\/a><\/i>.<\/p>\nThe Earth is now warming faster than at any time in the last 11,000 years, but scientists do not understand clearly why the atmosphere has warmed less than they expected over the last decade or so, and more slowly than in the 1990s.<\/p>\n
The researchers looked at how the last decade would affect the long-term sensitivity of the climate to a doubling of atmospheric concentrations of carbon dioxide, and suggest the Earth will warm more slowly than expected this century.<\/p>\n
But even though the heating may be slower, giving politicians more time to act, the scientists still believe temperatures will eventually climb to 4\u00b0C above pre-industrial levels, well above danger levels.<\/p>\n
Clive Hamilton<\/a> is professor of public ethics at Charles Sturt University, Australia, and author of Requiem for a Species: Why we resist the truth about climate change<\/a><\/i>. Published in 2010, it says climate change will bring about large-scale, harmful consequences for life on Earth which it is too late to prevent.<\/p>\nProfessor Hamilton told Climate News Network: \u201cThe study should certainly be taken very seriously, although we will need to see over the next year or two how well it stands up to scrutiny. Let\u2019s hope they are right; it\u2019s the first bit of good news we have had a for a long time.\u201d<\/p>\n
Too soon to say<\/b><\/p>\n
Dr Geoff Jenkins is the former head of climate change prediction at the UK Met Office\u2019s Hadley Centre for Climate Prediction and Research<\/a>. He told the Network: \u201cUntil we actually understand why the global temperature rise has paused over the last decade \u2014 and we don\u2019t yet – it\u2019s still guesswork what the implications are for climate sensitivity and hence the future projections.<\/p>\n\u201cIf the pause is a \u2018correction\u2019 to a naturally-boosted rise over previous decades, then maybe the climate sensitivity is indeed lower than the Intergovernmental Panel on Climate Change<\/a>\u2019s central estimate and future rises will be towards the lower end of the range.<\/p>\n\u201cBut if the pause is a temporary natural offset to the man-made rise, then this offset would disappear at some stage and put us back on the central estimate track. I don\u2019t see how we can say which it is until we understand the reason for it.\u201d<\/p>\n
Many governments have promised to try to limit atmospheric warming to no more than 2 \u00b0C above pre-industrial levels, believing that threshold will prevent dangerous climate change.<\/p>\n
Previous estimates showed that would require global greenhouse gas emissions to peak by 2020 and then fall, a prospect that seemed out of reach while emissions continue to rise fast.<\/p>\n
Another member of the research team is Professor Myles Allen, also of ECI Oxford. \u201cPrior to this, a lot of us were feeling quite gloomy that whatever we did, we\u2019ll go over 2 \u00b0C\u201d, he said. \u201cIt\u2019s not a foregone conclusion any more.\u201d<\/p>\n
That means the protracted UN climate negotiations could still produce a workable agreement. If a deal enters force in 2020 and leads to rapid emissions cuts, \u201cthere remains a good chance we could hit the 2\u00b0C target\u201d, Professor Allen says.<\/p>\n
Models \u2018pretty accurate\u2019<\/b><\/p>\n
Explanations for the current pause are the masking effects on greenhouse gases of pollution, the seasonal weather-disrupting El Ni\u00c3\u00b1o phenomenon, and slight variations in the Sun\u2019s output. It also appears that much of the heat has been going, not into the atmosphere, but into the oceans.<\/p>\n
What Dr Otto and his colleagues have done is to estimate how much warming, with rising emissions, the world is likely to experience by the time carbon dioxide levels have doubled since pre-industrial times. Their most likely estimate is 1.3\u00b0C, not the rise of up to 1.6 \u00b0C suggested by previous studies.<\/p>\n
\u201cIn the short term, there is maybe a bit less warming than expected,\u201d said Dr Otto. But he told the London Guardian<\/a><\/i> that the findings of his team\u2019s research did not constitute evidence that climate change had stopped.<\/p>\nHe said: \u201cGiven the noise in the climate and temperature system, you would need to see a much longer period of any pause in order to draw the conclusion that global warming was not occurring.\u201d Such a period could be as long as 40 years. The team\u2019s study had found that most of the climate change models used by scientists were \u201cpretty accurate\u201d.<\/p>\n
On such a contentious subject some scientists would argue for caution in evaluating the research. A rise of 4\u00b0C in global average temperatures could mean far higher regional rises. The oceans are likely one day to give up much of the heat they are now absorbing, which will return to the atmosphere.<\/p>\n
So warming could accelerate fast and unpredictably. And on present trends, fossil fuel use is likely to go on increasing for several decades at least.<\/p>\n
There are qualifications and conditions in the research, \u201cifs\u201d and \u201cbuts\u201d which suggest there may be unknown unknowns ahead. Its conclusion is that the world is still warming \u2014 much too fast for comfort.\n<\/p>\n
![\"\"](\"http:\/\/www.truthdig.com\/images\/eartothegrounduploads\/6993002080_e95a0d0f4b.jpg\")
<\/p>\n
NASA Earth Observatory<\/a> (CC BY 2.0)<\/a><\/p>\n<\/span>\n<\/div>\n
By Alex Kirby, Climate News Network<\/b><\/p>\n
This piece first appeared at Climate News Network<\/a>.<\/i><\/p>\n LONDON\u2013Several leading authorities on climate change have given a guarded welcome to research suggesting the Earth may warm more slowly than scientists had expected.<\/p>\n An international research team led by Dr Alexander Otto of the Environmental Change Institute<\/a> (ECI) at the University of Oxford, UK, has reported its conclusions in the journal Nature Geoscience<\/a><\/i>.<\/p>\n The Earth is now warming faster than at any time in the last 11,000 years, but scientists do not understand clearly why the atmosphere has warmed less than they expected over the last decade or so, and more slowly than in the 1990s.<\/p>\n The researchers looked at how the last decade would affect the long-term sensitivity of the climate to a doubling of atmospheric concentrations of carbon dioxide, and suggest the Earth will warm more slowly than expected this century.<\/p>\n But even though the heating may be slower, giving politicians more time to act, the scientists still believe temperatures will eventually climb to 4\u00b0C above pre-industrial levels, well above danger levels.<\/p>\n Clive Hamilton<\/a> is professor of public ethics at Charles Sturt University, Australia, and author of Requiem for a Species: Why we resist the truth about climate change<\/a><\/i>. Published in 2010, it says climate change will bring about large-scale, harmful consequences for life on Earth which it is too late to prevent.<\/p>\n Professor Hamilton told Climate News Network: \u201cThe study should certainly be taken very seriously, although we will need to see over the next year or two how well it stands up to scrutiny. Let\u2019s hope they are right; it\u2019s the first bit of good news we have had a for a long time.\u201d<\/p>\n Too soon to say<\/b><\/p>\n Dr Geoff Jenkins is the former head of climate change prediction at the UK Met Office\u2019s Hadley Centre for Climate Prediction and Research<\/a>. He told the Network: \u201cUntil we actually understand why the global temperature rise has paused over the last decade \u2014 and we don\u2019t yet – it\u2019s still guesswork what the implications are for climate sensitivity and hence the future projections.<\/p>\n \u201cIf the pause is a \u2018correction\u2019 to a naturally-boosted rise over previous decades, then maybe the climate sensitivity is indeed lower than the Intergovernmental Panel on Climate Change<\/a>\u2019s central estimate and future rises will be towards the lower end of the range.<\/p>\n \u201cBut if the pause is a temporary natural offset to the man-made rise, then this offset would disappear at some stage and put us back on the central estimate track. I don\u2019t see how we can say which it is until we understand the reason for it.\u201d<\/p>\n Many governments have promised to try to limit atmospheric warming to no more than 2 \u00b0C above pre-industrial levels, believing that threshold will prevent dangerous climate change.<\/p>\n Previous estimates showed that would require global greenhouse gas emissions to peak by 2020 and then fall, a prospect that seemed out of reach while emissions continue to rise fast.<\/p>\n Another member of the research team is Professor Myles Allen, also of ECI Oxford. \u201cPrior to this, a lot of us were feeling quite gloomy that whatever we did, we\u2019ll go over 2 \u00b0C\u201d, he said. \u201cIt\u2019s not a foregone conclusion any more.\u201d<\/p>\n That means the protracted UN climate negotiations could still produce a workable agreement. If a deal enters force in 2020 and leads to rapid emissions cuts, \u201cthere remains a good chance we could hit the 2\u00b0C target\u201d, Professor Allen says.<\/p>\n Models \u2018pretty accurate\u2019<\/b><\/p>\n Explanations for the current pause are the masking effects on greenhouse gases of pollution, the seasonal weather-disrupting El Ni\u00c3\u00b1o phenomenon, and slight variations in the Sun\u2019s output. It also appears that much of the heat has been going, not into the atmosphere, but into the oceans.<\/p>\n What Dr Otto and his colleagues have done is to estimate how much warming, with rising emissions, the world is likely to experience by the time carbon dioxide levels have doubled since pre-industrial times. Their most likely estimate is 1.3\u00b0C, not the rise of up to 1.6 \u00b0C suggested by previous studies.<\/p>\n \u201cIn the short term, there is maybe a bit less warming than expected,\u201d said Dr Otto. But he told the London Guardian<\/a><\/i> that the findings of his team\u2019s research did not constitute evidence that climate change had stopped.<\/p>\n He said: \u201cGiven the noise in the climate and temperature system, you would need to see a much longer period of any pause in order to draw the conclusion that global warming was not occurring.\u201d Such a period could be as long as 40 years. The team\u2019s study had found that most of the climate change models used by scientists were \u201cpretty accurate\u201d.<\/p>\n On such a contentious subject some scientists would argue for caution in evaluating the research. A rise of 4\u00b0C in global average temperatures could mean far higher regional rises. The oceans are likely one day to give up much of the heat they are now absorbing, which will return to the atmosphere.<\/p>\n So warming could accelerate fast and unpredictably. And on present trends, fossil fuel use is likely to go on increasing for several decades at least.<\/p>\n There are qualifications and conditions in the research, \u201cifs\u201d and \u201cbuts\u201d which suggest there may be unknown unknowns ahead. Its conclusion is that the world is still warming \u2014 much too fast for comfort.\n<\/p>\n NASA Earth Observatory<\/a> (CC BY 2.0)<\/a><\/p>\n <\/span>\n<\/div>\n<\/p>\n