Experts Surer Than Ever of Manmade Global Warming

By Alister Doyle on 10:00 am Aug 17, 2013

Oslo. Climate scientists are surer than ever that human activity is causing global warming, according to leaked drafts of a major UN report, but they are finding it harder than expected to predict the impact in specific regions in coming decades.

The uncertainty is frustrating for government planners: the report by the Intergovernmental Panel on Climate Change (IPCC) is the main guide for states weighing multibillion-dollar shifts to renewable energy from fossil fuels, for coastal regions considering extra sea defenses or crop breeders developing heat-resistant strains.

Drafts seen by Reuters of the study by the UN panel of experts, due to be published next month, say it is at least 95 percent likely that human activities – chiefly the burning of fossil fuels – are the main cause of warming since the 1950s.

That is up from at least 90 percent in the last report in 2007, 66 percent in 2001, and just over 50 in 1995, steadily squeezing out the arguments by a small minority of scientists that natural variations in the climate might be to blame.

That shifts the debate onto the extent of temperature rises and the likely impacts, from manageable to catastrophic.

Governments have agreed to work out an international deal by the end of 2015 to rein in rising emissions.

“We have got quite a bit more certain that climate change … is largely manmade,” said Reto Knutti, a professor at the Swiss Federal Institute of Technology in Zurich. “We’re less certain than many would hope about the local impacts.”

And gauging how warming would affect nature, from crops to fish stocks, was also proving hard since it goes far beyond physics. “You can’t write an equation for a tree,” he said.

The IPCC report, the first of three to be released in 2013 and 2014, will face intense scrutiny, particularly after the panel admitted a mistake in the 2007 study which wrongly predicted that all Himalayan glaciers could melt by 2035.

Experts say the error far overestimated the melt and might have been based on a misreading of 2350.

The new study will state with greater confidence than in 2007 that rising manmade greenhouse gas emissions have already meant more heatwaves. But it is likely to play down some tentative findings from 2007, such as that human activities have contributed to more droughts.

Almost 200 governments have agreed to try to limit global warming to below 2 degrees Celsius above pre-industrial times, seen as a threshold for dangerous changes including more droughts, extinctions, floods and rising seas that could swamp coastal regions and entire island nations.

The report will flag a high risk that global temperatures will increase this century by more than that level, and will say that evidence of rising sea levels is now “unequivocal”.

For all that, scientists say it is proving harder to pinpoint local impacts in coming decades in a way that would help planners.

Drew Shindell, a NASA climate scientist, said the relative lack of progress in regional predictions was the main disappointment of climate science since 2007.

“I talk to people in regional power planning. They ask: ‘What’s the temperature going to be in this region in the next 20-30 years, because that’s where our power grid is?’” he said.

“We can’t really tell. It’s a shame,” said Shindell. Like the other scientists interviewed, he was speaking about climate science in general since the last IPCC report, not about the details of the latest drafts.

Warming Slowing

The panel will try to explain why global temperatures, while still increasing, have risen more slowly since about 1998 even though greenhouse gas concentrations have hit repeated record highs in that time, led by industrial emissions by China and other emerging nations.

An IPCC draft says there is “medium confidence” that the slowing of the rise is “due in roughly equal measure” to natural variations in the weather and to other factors affecting energy reaching the Earth’s surface.

Scientists believe causes could include: greater-than-expected quantities of ash from volcanoes, which dims sunlight; a decline in heat from the sun during a current 11-year solar cycle; more heat being absorbed by the deep oceans; or the possibility that the climate may be less sensitive than expected to a build-up of carbon dioxide.

“It might be down to minor contributions that all add up,” said Gabriele Hegerl, a professor at Edinburgh University. Or maybe, scientists say, the latest decade is just a blip.

The main scenarios in the draft, using more complex computer models than in 2007 and taking account of more factors, show that temperatures could rise anywhere from a fraction of 1 degree Celsius to almost 5C this century, a wider range at both ends than in 2007.

The low end, however, is because the IPCC has added what diplomats say is an improbable scenario for radical government action – not considered in 2007 – that would require cuts in global greenhouse gases to zero by about 2070.

Temperatures have already risen by 0.8C since the Industrial Revolution in the 19th century.

Experts say that the big advance in the report, due for a final edit by governments and scientists in Stockholm from Sept. 23-26, is simply greater confidence about the science of global warming, rather than revolutionary new findings.

Sea Levels

“Overall our understanding has strengthened,” said Michael Oppenheimer, a professor at Princeton University, pointing to areas including sea level rise.

An IPCC draft projects seas will rise by between 29 and 82 cm by the late 21st century – above the estimates of 18 to 59 cm in the last report, which did not fully account for changes in Antarctica and Greenland.

The report slightly tones down past tentative findings that more intense tropical cyclone are linked to human activities.

Warmer air can contain more moisture, however, making downpours more likely in future.

“There is widespread agreement among hurricane scientists that rainfall associated with hurricanes will increase noticeably with global warming,” said Kerry Emanuel, of the Massachusetts Institute of Technology.

“But measuring rainfall is very tricky,” he said.

Reuters

  • Danilo Bertocchi

    may be it would good you get informed. we have very accurate datas from numerous sources and able to study paleoclimatology. But there is no energy waste trying to convince deniers

  • TalkingEid

    As usual, lots of hot air from the ‘experts’ (I wonder who funds their research?) and not much real science.

    • Brian Derrick

      And your qualifications to make such an assessment are…???

      • TalkingEid

        Its not MY qualifications in question – I’m not seeking massive funding to research global warming.
        Please someone – point me at some real scientific evidence of man-made global warming – I’d be really happy to see that public money is not being squandered.
        By the way the question – who funds their research – is rhetorical. Much of the research is funded by environmental groups – I doubt the dollars would keep flowing unless the the “results” suit them. Similarly, which ‘scientists’ will say – “Oh global warming doesn’t exist, my research proves it, no more dollars for me, thank you”
        I was taught to question everything – religion, science, politics…… I don’t accept being told what is correct and what is not, unless someone is prepared to back their views with solid evidence.
        Evidence please?
        Meanwhile I will watch George Carlin again …..

        • Forgetyourself

          Read the reports and take a course in climate science. Then you’ll understand. Guaranteed.

        • Valkyrie1604

          TE: I wouldn’t fret over this issue. It’s purely academic and some like to exhibit how much smarter they are than you. More fun with George.

        • Brian Derrick

          For someone so well informed about thermodynamic properties of gasses, a little late in the game to be asking for data, huh?

          I hope government sites are not too ‘liberal’. This should get you started:

          http://climate.nasa.gov/
          http://www.globalchange.gov/
          http://www.ipcc-data.org/
          http://www.epa.gov/climatechange/
          http://www.bom.gov.au/climate/change/

        • Brian Derrick

          Your understanding of the scientific processes is not just cynical – it’s wrong! If there were convincing data indicating climate change was reversing, climatologists would be all over it. The scientist who demonstrates climate change is an error will likely not only become famous, but will never have to write a grant again! We scientists live to disprove accepted dogma, and an ‘accepted fact’ is just a fact with a target bull’s eye on it. Please… stop making assumptions and conclusions about things you know nothing about and do not (or cannot) understand.

          • TalkingEid

            so – If I am wrong and you are right – where is the evidence?
            Or am I just supposed to take the word of ‘experts’ – in the same way I am supposed to take the word of those who believe in God?

        • Forgetyourself

          okay TalkingEid – you keep learning from George Carlin and let the rest of us get on with real science.

    • Brian Derrick

      Oh, and their funding? Given it’s a UN panel, it likely came from dozens of countries and national scientific agencies worldwide.

    • Forgetyourself

      You obviously have no idea about climate science or who funds the IPCC.

  • Lucky Sausage eater

    Bill
    In fact 160 years worth of meaningful records (sea levels, temps, seat temps) plus of cause millions of years of ice data, which is data trapped in the ice caps which is extrapolated to give a decent picture. This of course is cross checked with rock data, showing sea levels concentrations of gaseous deposits even vegetation records. We don’t just guess or rely on god.
    But I agree with Dan

  • gopher652003

    That isn’t really the issue. Whether or not Earth had higher temperatures 50 million years ago doesn’t affect us today. What does have an effect on us is the possibility that, as just one example of many bad outcomes, sea levels could rise 50 centimeters (19 to 20 inches). Why is that important in the grand scheme of the planet? Well, it obviously isn’t. It’s happened before and it will happen again. The planet as a whole (and us too) will survive. Short term though things are different.

    You see, unfortunately for us, we’ve built a large part of our civilization right smack on the edge of the ocean. A 20 inch rise will either necessitate trillions of dollars in new seawall construction to prevent largescale flooding, or trillions of dollars in costs to relocate and rebuild infrastructure a few miles inland.

    That money has to come from somewhere. If it comes from the private sector’s pockets they’ll have less to spend on everything else, really slowing down the worldwide economy (especially countries like the US that produce a lot of technically unnecessary luxury goods). If it comes from governments we can all look forward to significant tax increases and major cuts in current services in order to pay for it. Both of those will hurt the economy too.

    So you see, it’s a lose lose scenario. Not because Earth will be irrevocably damaged, but rather due to the huge long term economic damage that will be caused by our failure to act. It’s already too late to prevent those trillions in future expenditures. Nothing we do now will stop that future from occurring.

    What we can do is prevent the further quadrillions of future expenditures that will be necessary if climate change continues unchecked.

  • TerrestrialAliens

    HAHA the IPCC are actually a CONSERVATIVE bunch the real truth is unfortunately far scarier I mean what do you expect from a group that has to be peer reviewed by oil producing countries. It is not that the oil companies are trying to prove global warming is man made, that would be absolutely stupid, now wouldn’t it. The only logical conclusion is that they are trying delay the findings and nothing more. HAHA the truth, it’s far too late to do a thing about it. If the ticket to Mars is still for sale I suggest that we take it.

  • bgrnathan

    GLOBAL WARMING MAY NOT BE MAN MADE

    Dr. Larry Vardiman (scientist and physicist) of the Institue for Creation Research says:

    “One possible scenario may be found
    in a recent series of articles by Henrik Svensmark and Nigel Marsh,
    cosmic ray specialists from Denmark, who have shown an indirect
    connection between galactic cosmic ray (GCR) intensity and global
    temperature.7,8,9 They are studying the influence of the Sun on the flow
    of GCR to Earth. The Sun’s changing sunspot activity influences the
    magnetosphere surrounding the Earth permitting more GCR to strike the
    Earth during high periods of activity.

    When the Sun is active, the intensity of GCR striking the Earth is
    increased, causing more ionization in the atmosphere, creating more
    carbon-14, and possibly creating more cloud condensation nuclei (CCN).
    This increase in CCN, in turn, appears to create more low-level clouds
    which cool the Earth. When the Sun is quiet the GCR intensity striking
    the Earth is reduced, allowing the Earth to warm. Svensmark and Marsh
    have shown a striking statistical correlation between sunspot activity
    and global cooling and warming over the past 1000 years.

    The recent rise in global temperature may partially be due to
    current low solar activity supplemented by a recent increase in carbon
    dioxide concentration measured at Mauna Loa. The connection which still
    needs further study is the production of CCN and clouds by GCR.”

    There is a good deal of science showing that global warming is not
    mad made. Yes, we still should have pollution controls, as we already
    do, but not to the extreme because it will unnecessarily hurt business.

    Visit my newest Internet site: THE SCIENCE SUPPORTING CREATION

    Babu G. Ranganathan
    B.A. Bible/Biology

    Author of popular Internet article, TRADITIONAL DOCTRINE OF HELL EVOLVED FROM GREEK ROOTS

    • realclimate

      problem here is that there has not been any changes in GCR intensityver recent decades, no correlation whatsoever

  • Bill Smith2

    This stuff IS the proverbial kool-aid.. Lotsa money in going greeeeen.. You think politicians really care about you? har har

    • Forgetyourself

      Bill – politicians would much rather ignore climate change, as most of them do. Its not a issue to tackle that will win many votes, especially in the US.
      Also, we are not debating whether politicians care about us either. The discussion is about whether the climate warming that we are currently experiencing is caused by human actions. There is of course natural climate forcing, but most of the current warming is caused by increased GHGs as a result of human actions.

      • Bill Smith2

        GHG that have only been produced by man over just the tiniest of fractions of how old the world is.. Try doing the math on it.. Its such a ridiculous fraction, based on 4 billion years, that it comes back with “to the ump-teenth” power!! .. Fractions that 99% of us in the real world never use, outside of high school ofcourse..

        If you think you or science can tell what the avg temp in Greenland was between Sept 8th 350,000 BC and June 2nd 348,390 (1400 years more than the combustion engine has been around currently) within a few degrees………..then I have some swampland in Florida you may be interested in..

        • Forgetyourself

          You are misunderstanding the problem Bill. It’s not about the age of the earth in relation to the fraction of GHGs. The age of the earth has zero impact on today’s changing climate. What matters is the sustained increasing rate of GHGs that are being added to the atmosphere thus trapping more and more outgoing infrared radiation from Earth. Evidence shows that our current high atmospheric concentrations of CO2, CH4 and N20 are unprecedented over the 16000 years. CO2 has risen by more that 30%. This evidence comes from ice cores, among others, and is very accurate. These increase concentrations of GHGs are trapping more heat and warming the planet. This, among other factors, is what matters.

          Ill repeat – the age of the Earth has NOTHING to do with current increases in temperature.

          You are clearly showing your ignorance of climate science in every post you write.

  • Bill Smith2

    Its called “faith” for a reason

  • gopher652003

    … not all ice floats in the ocean;). A great deal of it sits in Greenland and Antarctica. But you’re right about the ice floating on the ocean.

    If the Arctic ice cap melted completely between now and 5 minutes from now the sea level wouldn’t rise at all. Course it would still have an impact – it would probably disturb the northern currents in the Atlantic and put western Europe into a temporary deepfreeze – but it wouldn’t touch the ocean level.

  • Forgetyourself

    WebEd – please post my replies to TalkingEid.

  • Forgetyourself

    TalkingEid: Please provide the name of a respected climate scientist who is associated with an environmental lobby and shouts ‘believe us we are scientists so it must be true’
    That is not the behaviour of intelligent respected scientists who publish in peer reviewed publications, but rather a bunch of idiots who have an agenda.
    Maybe you need to spend more time reading the real science and not the other rubbish.

  • TalkingEid

    Youre right I’m not a scienist – I’m a sceptic – show me PROOF – not “very likely’ and I will believe it.
    meanwhile I will treat these ‘experts’ with the same scepticism that I treat all ‘experts’ – including scientists, who have appointed themselves the new High Priests of the world – “believe me because I say it is true”.

    • Forgetyourself

      Scientists are skeptics by nature. It’s our job to be skeptical – double check and peer review everything until the highest levels of certainty can be reached. That is how science progresses.

  • TalkingEid

    How do we know? Show me the PROOF.

  • TalkingEid

    “It is not possible for the sea levels to fall if the ice caps melt” – prove it. Show me the calculations.

  • Forgetyourself

    The issue is not highly controversial at all. In fact, if you were better informed, you would know that there is broad consensus among the scientific community. You are not speaking the truth Valkyrie

    • Valkyrie1604

      I hesitated, but here’s my response.

      A little boy once asked me (a long time ago) why there are so many differences in this world which has so many intelligent people?

  • Forgetyourself

    TalkingEid – You didn’t bother reading the IPCC report, did you? LOL

    • TalkingEid

      No – Im waiting for one of the ‘expert scientist’ on here to provide proof of the theory of man made global warming.