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Must re-read statement from UK’s Royal Society and Met Office on the connection between global warming and extreme weather

By Joe Romm on February 13, 2010 at 3:35 pm

"Must re-read statement from UK’s Royal Society and Met Office on the connection between global warming and extreme weather"

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We expect some of the most significant impacts of climate change to occur when natural variability is exacerbated by long-term global warming, so that even small changes in global temperatures can produce damaging local and regional effects. Year on year the evidence is growing that damaging climate and weather events — potentially intensified by global warming — are already happening and beginning to affect society and ecosystems. This includes:


  • In the UK, heavier daily rainfall leading to local flooding such as in the summer of 2007;
  • Increased risk of summer heat waves such as the summers of 2003 across the UK and Europe;
  • Around the world, increasing incidence of extreme weather events with unprecedented levels of damage to society and infrastructure. This year’s unusually destructive typhoon season in South East Asia, while not easy to attribute directly to climate change, illustrates the vulnerabilities to such events;
  • Sea level rises leading to dangerous exposure of populations in, for example, Bangladesh, the Maldives and other island states;
  • Persistent droughts, leading to pressures on water and food resources, and the increasing incidence of forest fires in regions where future projections indicate long term reductions in rainfall, such as South West Australia and the Mediterranean.

These emerging signals are consistent with what we expect from our projections, giving us confidence in the science and models that underpin them. In the absence of action to mitigate climate change, we can expect much larger changes in the coming decades than have been seen so far.

That is from the November statement by the Met Office (the UK’s National Weather Service [i.e. meteorological office], within the Ministry of Defence), the Natural Environment Research Council, and the UK’s Royal Society (the UK’s national academy of science, “the world’s oldest scientific academy in continuous existence,” founded in 1660).

The Royal Society’s motto is apt:  Nullius in verba — Latin for “On the words of no one” or “take nobody’s word for it.”  It is “an expression of its enduring commitment to empirical evidence as the basis of knowledge about the natural world.”

I posted it when in first came out three months ago.  After rereading it today (for reasons that will become clear), I realized the one-time must-read statement is must-reread statement — because of its thoughtful discussion of extreme weather in a globally warmed world (and its statement about the IPCC).

As I’ve noted many times, the anti-science disinformers try to shout down any talk of a link between climate change and extreme weather.  But  “the evidence is growing that damaging climate and weather events — potentially intensified by global warming — are already happening and beginning to affect society and ecosystems.”

Human-caused global warming has clearly increased the likelihood of certain events — like the epic European heat wave of 2003.

It has potentially intensified other events — see Australian Scientists: Contrary to media reports, “our paper does not discount climate change as playing a role in this most recent drought, the ‘Big Dry’. In fact, there are indications that climate change has worsened this recent drought.” Indeed,”we expect some of the most significant impacts of climate change to occur when natural variability [like, say, El Ni±o] is exacerbated by long-term global warming.”

And yet other events — like the heavier precipitation that the UK and other countries (including the U.S.) have experienced — “are consistent with what we expect from our projections, giving us confidence in the science and models that underpin them.”

And if we fail to take action, we can expect even larger changes than we have seen so far and “impacts on climate and civilisation could be severe.”

That is a perfectly appropriate — even necessary — way to talk about extreme weather events in a globally warmed world.

Here’s the whole statement:

The UK is at the forefront of tackling dangerous climate change, underpinned by world class scientific expertise and advice. Crucial decisions will be taken soon in Copenhagen about limiting and reducing the impacts of climate change now and in the future. Climate scientists from the UK and across the world are in overwhelming agreement about the evidence of climate change, driven by the human input of greenhouse gases into the atmosphere.

As three of the UK’s leading scientific organisations involving most of the UK scientists working on climate change, we cannot emphasise enough the body of scientific evidence that underpins the call for action now, and we reinforce our commitment to ensuring that world leaders continue to have access to the best possible science. We believe this will be essential to inform sound decision-making on policies to mitigate and adapt to climate change up to Copenhagen and beyond.

The 2007 Assessment Report of the UN’s climate change panel (the IPCC) — made up of the world’s foremost climate scientists — provided unequivocal evidence for a warming climate, and a high degree of certainty that human activities are largely responsible for global warming since the middle of the 20th century. However, the IPCC process is based only on information already published and even since the last Assessment Report the scientific evidence for dangerous, long-term and potentially irreversible climate change has strengthened significantly:

  • Global carbon dioxide concentrations continue to rise, and methane concentrations have started to increase again after a decade of near stability;
  • The decade 2000-2009 has been warmer, on average, than any other decade in the previous 150 years;
  • Observed changes in precipitation (decreases in the subtropics and increases in high latitudes) have been at the upper limit of model projections;
  • Arctic summer sea ice cover declined suddenly in 2007 and 2008, prompting the realisation that this environment may be far more vulnerable to change than previously thought;
  • There is increasing evidence of continued and accelerating sea-level rises around the world.

We expect some of the most significant impacts of climate change to occur when natural variability is exacerbated by long-term global warming, so that even small changes in global temperatures can produce damaging local and regional effects. Year on year the evidence is growing that damaging climate and weather events — potentially intensified by global warming — are already happening and beginning to affect society and ecosystems. This includes:

  • In the UK, heavier daily rainfall leading to local flooding such as in the summer of 2007;
  • Increased risk of summer heat waves such as the summers of 2003 across the UK and Europe;
  • Around the world, increasing incidence of extreme weather events with unprecedented levels of damage to society and infrastructure. This year’s unusually destructive typhoon season in South East Asia, while not easy to attribute directly to climate change, illustrates the vulnerabilities to such events;
  • Sea level rises leading to dangerous exposure of populations in, for example, Bangladesh, the Maldives and other island states;
  • Persistent droughts, leading to pressures on water and food resources, and the increasing incidence of forest fires in regions where future projections indicate long term reductions in rainfall, such as South West Australia and the Mediterranean.

These emerging signals are consistent with what we expect from our projections, giving us confidence in the science and models that underpin them. In the absence of action to mitigate climate change, we can expect much larger changes in the coming decades than have been seen so far.

Some countries and regions are already vulnerable to climate variability and change, but in the coming decades all countries will be affected, regardless of their affluence or individual emissions. Climate change will have major consequences for food production, water availability, ecosystems and human health, migration pressures, and regional instability. In the UK, we will be affected both directly and indirectly, through the effects of climate change on, for example, global markets (notably in food), health, extent of flooding, and sea levels.

The accumulation of carbon dioxide in the atmosphere will lead to long-term changes in the climate system that will persist for millennia. Our growing understanding of the balance of carbon between the atmosphere, oceans and terrestrial systems tells us that the greater the accumulation of carbon dioxide in the atmosphere, the greater the risk of long-term damage to Earth’s life support systems. Known or probable damage includes ocean acidification, loss of rain forests, degradation of ecosystems, and desertification. These effects will lead to loss of biodiversity and reduced agricultural productivity. Reducing emissions of greenhouse gases can substantially limit the extent and severity of long-term climate change.

Summary

The 2007 IPCC Assessment, the most comprehensive and respected analysis of climate change to date, states clearly that without substantial global reductions of greenhouse gas emissions we can likely expect a world of increasing droughts, floods and species loss, of rising seas and displaced human populations. However even since the 2007 IPCC Assessment the evidence for dangerous, long-term and potentially irreversible climate change has strengthened. The scientific evidence which underpins calls for action at Copenhagen is very strong. Without co-ordinated international action on greenhouse gas emissions, the impacts on climate and civilisation could be severe.

Professor Julia Slingo, Chief Scientist, Met Office
Professor Alan Thorpe, Chief Executive, NERC
Lord Rees, President, the Royal Society

Hear!  Hear!

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18 Responses to Must re-read statement from UK’s Royal Society and Met Office on the connection between global warming and extreme weather

  1. prokaryote says:

    The Pliocene Paradox (Mechanisms for a Permanent El Niño)
    http://www.sciencemag.org/cgi/content/abstract/312/5779/1485

  2. Andy says:

    “These emerging signals..”

    Yes, they are just now emerging and can only be detected using the long global weather record and statistics.

    Scientists realize that global warming will become more and more apparent as time goes on, but until then they expect droughts to be broken and heat spells to be followed by cold snaps.

    I’d like to hear an expert’s opinion, but my guess is that it will be another 30 years (and another 1 degree C of warming) before it is obvious to everyone that we are in trouble. I’m not saying we need to wait until then to do something, but rather to be careful and not overreach with statements about the weather.

    As an example: the prediction that Lake Powell in Arizona and Nevada will one day go dry. The prediction was made while the reservoir was dropping quickly and many were saying it was going dry then. But the scientists trusted their data and models and said: “No, it is likely the lake will return to full conditions. But eventually, probably within 50 years, increased withdrawals, hotter temperatures, and less rainfall and snowfall will probably cause it to go dry.”

    [JR: I think it is 10 to 15 years at most, except for the most diehard ant-science crowd. Things are accelerating. The Arctic will likely go nearly ice free in that time. Should be a big shock.]

  3. ken levenson says:

    sorry to go off topic but have you seen this latest Bill Gates spouting?
    via
    http://news.mongabay.com/2010/0212-gates.html

    “Gates said the world needs to reduce carbon emissions to zero by 2050 and suggested researchers spent the next 20 years developing new technologies and the follow 20 years implementing them. He said coal and natural gas should be phased out by 2050 and touted carbon capture and storage technology and wind, solar photovoltaic and solar thermal, and nuclear power.”

    sounds very Breakthrough Institute…. Can he be made to understand that we essentially have the technology now?

    [JR: I'm on it!]

  4. Wit's End says:

    Andy, maybe a little tour around the Desdemona Despair archives will alter your perception of the current extremes wrought by climate change, which are already quite apparent to those experiencing them in other parts of the world. Here are two of the most recent posts:

    http://www.desdemonadespair.net/2010/02/worst-mongolia-winter-in-30-years-could.html

    http://www.desdemonadespair.net/2010/02/worst-heatwave-in-50-years-roasts-rio.html

  5. prokaryote says:

    Andy, you seem to be deeply concerned.

    It is happening now – today.

  6. jon says:

    I think UK and Scandinavia will be really affected when the ocean conveyer belt is stopped from too much fresh water being dumped into the atlantic ocean and all that warm water from the gulf of mexico and the caribbean stops warming UK and Scandinavian countries, this has happened before.

    There are reports that this is slowing down the gulf stream now.

  7. Bill Waterhouse says:

    Re #1 and a possible permanent El Nino – here is a NASA simulation of Pliocene climate:

    http://www.giss.nasa.gov/research/features/199704_pliocene/page2.html

  8. Nick says:

    RichieP,you wouldn’t know reality from a hole in the ground,the one you dug from spinning on the spot.

    Having read Jones’ interview at the BBC,I’m not surprised you’re desperate to spin it. “Yes,some of my record-keeping was untidy,yes,I wish I hadn’t reacted to denialist bating,yes,we will never know the MWP with the certainty that we know the modern era.” That is enough to fuel your triumphalism? Ffft.

  9. Zach says:

    I wonder whether, as a persuasive device, pointing out that extreme weather increases with global warming is productive on the whole. The science points that way and empirical evidence backs it up. However, it seems to invite the unfortunately compelling argument that extremely cold weather anywhere negates global warming.

    Perhaps it would be best to make the point generally, but not to connect specific extreme weather events to global warming. Show a plot of the number of blizzards per year in North America paired with global temperature change (no clue what this would look like, but you get the point).

    The rhetorical strength of these points suffers when you have to include the caveat, “while not easy to attribute directly to climate change,” every time you talk about any specific event.

  10. Wit's End says:

    Zach, we’re not having extremely COLD weather. We’re having extreme PRECIPITATION.

    In New Jersey, which took the brunt of the last blizzard, it’s NOT COLD! We have daffodils and witchhazel buds emerging 2 months ahead of schedule already.

    Heavier precipitation IS predicted to be a result of average global warming!

  11. Craig says:

    So the science says that the frequency of extreme weather events will increase as the planet warms. That is a prediction which will eventually either be validated or refuted. But do we have enough data in the historical record to conclusively demonstrate that the frequency of extreme events already has increased?

    At best, we may have 100 to 150 years of records to look at. For much of that time, the amount of warming was relatively modest (only 0.4C between 1860 and 1980, according to the East Anglia temperature trend). It seems like a difficult statistical problem to extract much of meaning from just the last couple of decades of unusual warmth, particularly if you are considering extreme events that are rare enough that they might normally only occur once every 20 or 50 or 100 years. Add in the possibility that there made be decades long climate oscillations that we don’t fully understand, and caution would seem to be in order about what has already been proven versus what is still to be proven.

  12. Andy says:

    Prokaryote: a very intriguing abstract. I wonder why I haven’t heard more about this at Real Climate, etc.? as the question of how it got so hot during the PETM is a big one (came up again this summer with the better estimates of carbon dioxide at that time.

    Craig: why did you stop your investigations of the globe’s temperature increase at 1980? Try as everyone in the whole freaking world might, no one has been able to assail the science of Mann’s latest hockey stick. Warmest it’s been in 2,000 years (at least) and the temperature is still going up.

  13. Lou Grinzo says:

    If we’re limited to responding to events after they begin to happen, then we may as well call in the dogs, put out the fire, and call it a day.

    The latency in the Earth system is so enormous, relative to human lifespans and response times, that we have no hope of avoiding impacts that would rival something out of a bad SF movie if we wait until “everyone” is “sure” it’s happening.

    We’re facing a humanity-wide intelligence test: Can enough of us understand the science and the threats it describes and then take action soon enough to avoid the you-know-what hitting the fan?

  14. Michael T. says:

    #9 Zach: No states this winter have had record cold. Most U.S. winters now don’t experience prolonged record cold anymore like they did in the 1960s and ’70s.

    Despite the cold snap in December and early January, no state had record cold as the NCDC finds.

    NCDC January 2010 summary:
    http://www.ncdc.noaa.gov/oa/climate/research/2010/jan/currentmonth.html

  15. Michael T. says:

    Let me clarify. Zach didn’t say “record cold” but extremely cold so I guess I wasn’t fair. I’m not sure if there is any difference. The point is, it’s already clear that the southern U.S. and Ohio and Tennessee Valley regions are going to have relatively cold winter. The rest of the country is near normal of much above normal.

  16. Meterman says:

    The rise in global average temperature is well established, as well as its cause.

    There seems to be a lot of uncertainty on how it is translated into weather (in a physical sense). Apparently the models are not yet comprehensive or detailed enough to explain how the large scale quasi-periodic processes (i.e. Arctic/Antarctic oscillations, PDO, ocean currents, etc.) respond.

    IMHO they form an intermediary step towards explaining changes in daily weather, extremes and so forth. Weather is what we experience. It is about understanding the causality, not just detecting a correlation.

  17. D.W. says:

    Here is another article trying to deny rising world temperatures by questioning temperature data stations. Note the last four paragraphs refute the headline and tenor of the remainder of the article (misleading):

    http://www.timesonline.co.uk/tol/news/environment/article7026317.ece

    Isn’t this a rehash of prior efforts to discredit data station quality?