Saturday round-up: Breathing space on CO2 cuts?

As well as satellite measurements, US National Oceanographic and Atmospheric Administration researchers used balloons at a single site in Boulder, Colorado, to find out how much water is in the stratosphere. (Credit NOAA)

Two major papers this week suggest that global warming is likely to accelerate at a slower pace than had previously been thought. In the first, Susan Solomon of the US National Oceanic and Atmospheric Administration has identified a possible cause of lower temperature increases in the noughties compared to the nineties. In the second, David Frank of the University of Bern in Switzerland suggests that the effect of a natural process that worsens man-made climate change has been overstated.

Together with a different set of Bern researchers, Solomon and colleagues in Boulder, Colorado, have shed some light on the poorly understood impact of water in the stratosphere on the world’s temperature. Water vapour in the stratosphere – the layer of the atmosphere above that which we live in – is known to cool that part of the atmosphere down but warm the troposphere underneath. However, it’s taken having satellites floating around the planet to measure accurately how much water is actually there.

The period in which measurements have been possible includes the rapid warming of the 1990s, and slower warming since. Solomon and her colleagues’ measurements show that water concentrations were higher during the warm period, and lower during the cool period. Creating computer models from these data suggest that the drop in stratospheric water vapour after 2000 decreased the rate of warming compared to what would have been otherwise expected by about 25%. The 1990s increase in water vapour could “have steepened the rate of global warming from 1990–2000 by about 30%,” the January 29 Science paper says. The researchers point out that it’s not yet known whether this is a feedback through which the earth tries to cool itself, or something that changes periodically.

The previous day, Frank’s team’s Nature paper tackled the question of just how much CO₂ is released from biological sources when the planet warms up, adding to what man is making by burning fossil fuels. “Approximately 40% of the uncertainty related to projected warming of the twenty-first century stems from the unknown behaviour of the carbon cycle,” they write. They evaluated all available large-scale temperature reconstructions and estimates of over the past thousand years. Their results suggest that the likely range of how much CO₂ is put into the atmosphere for each degree of warming is likely to be in the lower half of current estimates.

Although neither Frank’s or Solomon’s research team suggests that global warming is about to reverse, taken together they might mean that humanity has longer to fight it than previously thought.

Another process currently helping to cool the globe is the formation of clouds under the ozone hole in the Southern hemisphere, researchers revealed in Geophysical Research Letters on Wednesday. Higher winds that are linked to ozone loss whip up more sea spray, which creates more clouds. These clouds reflect heat from the sun back out into space, helping counteract greenhouse-gas based global warming. The link between the winds that create clouds and ozone loss could lead to the strange situation where a fully-repaired hole could lead to faster worldwide temperature rises.

Outside of climate research this week, a Yale and Mason University survey of 1001 US adults shows that only 57% think that global warming is happening in 2010, compared with 71% in a similar survey in 2008. The proportion that think it is not happening has doubled over that period, to 20% now. Regardless of which side of this debate you stand on, the silver lining may be the reduced amount of stress global warming is now causing Americans: The number who say that they are “very worried” about climate change has fallen from 17% in 2008, to 12% today.

“It just feels like the sun is getting closer to the Earth”

Oxfam climate campaigner Janine Woodward

The poorest parts of the world are set to be the most devastated by climate change and quotes like the one above, from a Ugandan woman, indicate that this might already be happening. The British charity Oxfam is campaigning hard to reduce global warming’s impact on the world’s poorest, driven partly by its observations of already increasing hardship.

Late last year I spoke to Janine Woodward, an Oxfam campaigner, shortly before she headed to Copenhagen to represent the charity’s members in my local region at the international climate negotiations. She explained why Oxfam feels that it must try to combat global warming, using the Ugandan woman’s words to help make her case.

“In Oxfam, we know that climate change is happening,” she told me. “Even if you take out the idea of why it’s happening, we know it’s happening because there are more natural disasters. We know that floods are getting worse around the world and we know that droughts are getting worse. We know that the people we’re trying to help with the aid work are suffering far more in the last 20 years than ever because their climate is changing.”

Woodward points out that more developed countries have been almost exclusively responsible for the increased CO₂ emissions that cause the greenhouse effect. She suggests that the same nations ought to take responsibility for preparing developing countries for the results its likely to have. And to those that say they shouldn’t take any such steps because of perceived weaknesses in the science surrounding climate change, she replies: “Well over 90% of climate scientists around the world believe that climate change is happening, and all of the top scientific institutions have signed up to statements that say that.”

In the end, the final agreement reached in Copenhagen fell some way short of what Woodward hoped for in order to keep global temperature rises below the 2°C level that is widely considered to be especially dangerous. That would have been a 40% cut in CO₂ by 2020 and an 80% by 2050. Nevertheless, everyone can help influence CO₂ emissions, she pointed out, not least by joining with charities and helping them campaign for action on a national and international level.

More immediate, practical, actions are also possible, Woodward explained. “I think if you change little things and over a year you change two, three, four things you can make a massive difference to your carbon emissions. The best thing that you can do to start with, I’d personally say, is change your electricity to a green tariff, so that your heating and your electricity usage is taken from renewable sources. Another thing that you can do is not necessarily give up your car, but maybe make one less car journey per week.”

“We do make a difference and we must stand in solidarity with those in suffering, and work to create a better world.”

Friday round-up: “Glaciergate” and climate research holes

False-colour image of the UK acquired on 8th January 2010, following heavy snow storms which saw the UK blanketed in snow. These images were captured by the Advanced Along-Track Scanning Radiometer (AATSR) instrument on board ESA’s ENVISAT satellite. The images were generated using three spectral channels: red - 0.87 microns; green - 0.67 microns; blue - 0.55 microns. Vegetated surfaces are much 'brighter' in the near infra red region (0.87 micron channel) than in the visible regions, therefore these regions appear more ‘red’. (Images courtesy of G. Corlett, University of Leicester)

Climate change researchers faced more public humiliation this week, as claims that the Himalayan glaciers were set to melt by 2035 were shown to be unfounded. The Intergovernmental Panel on Climate Change (IPCC), a United Nations body, included the claim in a 2007 report aimed to feed into international negotiations.

However, after questions about the claims were raised shortly prior to December’s Copenhagen summit, it emerged that they were not based on the usual peer-reviewed sources that the IPCC uses. Instead, the source referred to was a 2005 report by the Worldwide Fund for Nature. In turn, that report cited as its source a 1999 New Scientist article reporting claims made by a researcher made in a brief telephone interview, that never made it into an academic journal.

“Clear and well-established standards of evidence were not applied properly,” the IPCC said in response to the news. “The IPCC regrets this.” Nevertheless, it also stressed that it stood by its ultimate conclusion on glaciers:

“Widespread mass losses from glaciers and reductions in snow cover over recent decades are projected to accelerate throughout the 21^st century, reducing water availability, hydropower potential, and changing seasonality of flows in regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes), where more than one-sixth of the world population currently lives.”

With the IPCC having jointly won joint the 2007 Nobel peace prize with Al Gore for its efforts to disseminate knowledge on climate change, this is rightly judged to be a big knock to its credibility. Yet, the IPCC itself had already pointed out that climate science and scientists can be fallible, pointing out 54 ‘key uncertainties’ in the very same report containing the incorrect glacier claims. In this week’s Nature, Quirin Schiermeier points out that although these do not undermine the fundamental conclusion that humans are warming the climate, they do hamper efforts to plan for the future.

Schiermeier picks up on four major areas. In regional climate prediction, basic models don’t get more accurate than 1-3° of latitude, or 70-210 miles. This is especially troublesome in regions with varied terrain, for example when dealing with areas where two climatically different plains are separated by a mountain plateau. In precipitation, while models agree that global warming will dry equatorial areas and make areas nearer the poles wetter, they don’t agree on much else. Researchers are especially worried as their estimates for how much precipitation was due to change until now are already too small. In the third area, airborne liquid or solid particles in the form of atmospheric aerosols are thought to block and reflect heat from the sun. There is a great deal of uncertainty about how large an impact these have, especially given that nobody knows accurately how many particles are up there.

Tree rings are a particular cause for consternation. Used by modern researchers to get information about temperatures for the years before humanity had thermometers, some trees at northern latitudes now seem to be responding differently to temperature. No-one yet knows why and as long as this is the case, although evidence suggests that 1998 was the warmest year in a millennium, there will remain doubt. Yet even studies raising uncertainties show the current warming to be unprecedented, Schiermeier reports, and the IPCC again stands by its assertion that there is a greater than 90% chance that this is caused by human-produced increases in greenhouse gases.

The UK has recently been glacial: this has been picked upon by some as another reason why global warming is over-hyped. Contrary to such suggestions, Philip Eden, the president of the UK’s Royal Meteorological Society, chose to emphasise that the wonderful satellite photo above of the recent cold snap is “certainly not evidence that ‘climate change’ has ceased”. Instead he cites a number of factors, including a weak jet-stream and a blocking high-pressure system making it easier for cold Arctic winds to reach where I live than warmer Atlantic air. “Such year-to-year, regional anomalies are intrinsic; it is the long-term, global trend that is important when assessing climate change,” Eden said.

Could we cool the planet by copying volcanoes?

Mount Pinatubo erupts in 1991

In 1991, Mount Pinatubo in the Philippines erupted violently, causing what so many scientists and politicians are trying to achieve these days: a reduction in global temperatures. The second largest volcanic eruption of the 20^th century, Pinatubo threw approximately 20 billion tonnes of sulphur dioxide (SO₂) into the air. Afterwards, the SO₂ caused a proportion of the sun’s energy falling on the planet to be reflected back out into space. 1992 and 1993 were the two coolest years of the 1990s.

So, perhaps man could create a similar effect that would balance out any dangerous temperature rises. Or so suggests Stewart Brand, a biologist by training, and fountain of ideas, who I saw talk on Monday to promote his new book “Whole Earth Discipline”. Much of what Brand said addressed how to solve the problems that global warming will cause.

Brand would rather governments not step in and try to take charge of the response to global warming. However, he highlights the burning of coal for electricity as a big contributor to the greenhouse effect, and admits that governments will probably have to step in to cut back on this.

Likewise his other solutions – including increased uptake of nuclear power, wider acceptance of genetically-modified foods – need to be achieved on city-, country- or planet-wide scales. This is some way from what Simple Climate hopes to address – what any single individual can do. So, when this was the subject of the very last question of the evening even Brand, with his expertise, struggled.

Brand's new book

What he eventually advised was that each of us try and join in the “conversation”, about the issue. Whether we’re among those that he suggests take an almost religious, unshakeable, stand on the matter, either the believers, or the “denialists”. Or whether we’re among the group he calls “warmers”, people close to the scientific data that are convinced that man-made climate change is happening, which includes the vast majority of climatologists. And even the sceptics, those who question whether the climatologists have it right on scientific grounds and who Brand expects would continue to do so, even if the climatologist changed their minds. If everyone makes their voices heard, the right ideas and actions will emerge.

And on the matter of cooling the planet by copying volcanoes? Well, after seeing Brand I looked at a review paper from the prestigious science journal Nature in 1995 examining the effects of Pinatubo. It points out that as well as cooling the planet, the increase in atmospheric SO₂ attacked atmospheric ozone. With the world having just about successfully dealt with this one environmental threat – the hole in the ozone layer – do we want to literally open it up all over again? As Brand himself said on the matter: “More science needed”.

Saturday Roundup: 2009 second warmest year on record

Nasa's Global Land-Ocean Temperature Index

NASA has published data showing that 2009 was the second warmest year on record, offering a serious challenge to a popular alternative theory to man-made climate change. That theory blames global warming on increases in energy coming from the sun, but in 2009 the sun was the least active it has been for 100 years. The Skeptical Science blog does admit that this comparison, which it made earlier today, is “cheeky”, as using only small numbers of measurements like this can be misleading. However, author John Cook points out this is just the latest in a string of evidence showing that there has been no correlation between solar activity and the Earth’s temperature since 1975.

Meanwhile, Richard Katz of Cambridge University and Grae Worster of Oxford University have suggested that a large piece of the Antarctic may already be sliding into the sea. They have modelled how Antarctic ice sheets move, focussing especially on the “grounding line”, an underwater junction where floating ice sheets anchor to the sea bed. As the ocean warms, the ice melts from below, meaning that the grounding line rises ever higher up the Antarctic land mass. “Do recent changes represent a mounting, catastrophic collapse associated with unstable retreat of grounding lines or, rather, a steady and controlled adjustment?” Katz and Worster ask. From the results of the model, they conclude that unstable grounding line retreat may already be ongoing on a body of ice known as the Pine Island glacier. According to New Scientist, this would mean that the Pine Island glacier is now unavoidably set to lose half of its ice, creating a 24 cm sea rise over the next 100 years.

Few people reading this blog will live to see the full impact of that, but our actions today will be crucial in determining what the world does look like in the 22nd century. That’s the key message of a paper published online this week by a collaboration between scientists in the US, Austria, and the Netherlands. They modelled how CO₂ production must be reduced to keep global temperature rises below 2°C – a limit acknowledged in the Copenhagen accord – by 2100. Among a wide range of outcomes they model, to have a 50:50 chance of limiting warming below 2°C in 2100, emissions in 2050 would have to be 72% of what they were in 2000.

The good news this week was that investors representing $13 trillion of assets  called on the US and other nations to move quickly on meeting such targets. 450 US, European, and Australian signatories released a statement at the Investor Summit on Climate Risk, at the United Nations on Thursday. “We cannot wait for a global treaty,” the statement said, calling for rapid action on emission limits, energy efficiency and renewable energy. Let’s hope that their own actions, and those of the companies invest in, are also in line with what they demand from the authorities.

NASA has published data showing that 2009 was the second warmest year on record, offering a serious challenge to a popular alternative theory to man-made climate change. That theory blames global warming on increases in energy coming from the sun, but in 2009 the sun was the least active it has been for 100 years. The Skeptical Science blog does admit that this comparison, which it made earlier today, is “cheeky”, as using only small numbers of measurements like this can be misleading. However, author John Cook points out this is just the latest in a string of evidence showing that there has been no correlation between solar activity and the Earth’s temperature since 1975.

Meanwhile, Richard Katz of Cambridge University and Grae Worster of Oxford University have suggested that a large piece of the Antarctic may already be sliding into the sea. They have modelled how Antarctic ice sheets move, focussing especially on the “grounding line”, an underwater junction where floating ice sheets anchor to the sea bed. As the ocean warms, the ice melts from below, meaning that the grounding line rises ever higher up the Antarctic land mass. “Do recent changes represent a mounting, catastrophic collapse associated with unstable retreat of grounding lines or, rather, a steady and controlled adjustment?” Katz and Worster ask. From the results of the model, they conclude that unstable grounding line retreat may already be ongoing on a body of ice known as the Pine Island glacier. According to New Scientist, this would mean that the Pine Island glacier is now unavoidably set to lose half of its ice, creating a 24 cm sea rise over the next 100 years.

Few people reading this blog will live to see the full impact of that, but our actions today will be crucial in determining what the world does look like in the 22^nd century. That’s the key message of a paper published online this week by a collaboration between scientists in the US, Austria, and the Netherlands. They modelled how CO₂ production must be reduced to keep global temperature rises below 2°C – a limit acknowledged in the Copenhagen accord – by 2100. Among a wide range of outcomes they model, to have a 50:50 chance of limiting warming below 2°C in 2100, emissions in 2050 would have to be 72% of what they were in 2000.

The good news this week was that investors representing $13 trillion of assets today called on the US and other nations to move quickly on meeting such targets. 450 US, European, and Australian signatories released a statement at the Investor Summit on Climate Risk, at the United Nations on Thursday. “We cannot wait for a global treaty,” the statement released on Thursday said, calling for rapid action on emission limits, energy efficiency and renewable energy. Let’s hope that their own actions, and those of the companies invest in, are also in line with what they demand from the authorities.

What the leaked “Climategate” emails meant

Trevor Davies

The volume of the argument over climate change was turned up a notch at the end of November 2009, thanks to emails leaked from the Climatic Research Unit at the University of East Anglia. Shortly after the scandal broke I asked Trevor Davies, who was formerly a director of the CRU, and now has overall responsibility for research at the university, what it all meant. To start with, he told me: “There is no evidence that the research produced by CRU is flawed. On the contrary, it has been scrutinised and improved by the peer review process by which the global scientific community challenges and accepts new science. CRU’s research is consistent with other, independent, analyses, particularly two independent data sets in the US.”

As commentators locked horns, throwing up clouds of confusion, just a few of the hundreds of emails were the focus of the battle. Perhaps the most damning was a quote from the CRU’s Phil Jones in 1999, saying: “I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie, from 1981 onwards) and from 1961 for Keith’s to hide the decline.”

Researchers collect tree ring cores

The trick in question concerns tree rings. “This refers to a clever way of portraying in a diagram an analysis of, and compensation for, the breakdown in the strong relationship between tree-ring density and temperature in some parts of the world since the 1960s,” Davies told me. When compared to temperature data back as far as the middle ages and beyond, wood density increases have been directly proportional – until the second half of the 20^th century. Jones himself contributed to a paper published in Nature – arguably the most difficult scientific journal to get published in – explaining this phenomenon nearly twelve years ago. So, charts using trees to measure temperatures over the whole century would need to use the “Nature trick”, taking into account how the link between wood density and temperature changed.

Critics have also focused on Jones’ suggestions that emails should be deleted to prevent them being accessed using freedom of information laws. These have been mentioned closely alongside criticisms that the raw data used by the CRU scientists had not been made available. Together, these give a particularly worrying sense that perhaps measurements have been destroyed to exaggerate the case for global warming. As mentioned in the last blog entry, the UK’s Met Office, a key collaborator with the CRU, has now released the raw data, to be met by fresh accusations of selective use of measurements. No definitive proof has yet come to light to support such claims, Davies points out. “There is no evidence that data have been lost, inappropriately adjusted or hidden,” he said.

Jones’ apparent efforts to try and suppress research criticising CRU research via the peer review process that Davies celebrates are at the centre of a third common criticism. Peer review, gathering and sharing of information and an investigation into suppression of data are all on the agenda of the independent review that the CRU has commissioned. “This demonstrates the commitment of the university to transparency and integrity in research,” Davies told me. “This is the correct way of responding to the orchestrated furore, rather than the many irresponsible distortions which have appeared in the blogosphere and some media. If the review concludes that there are issues to address, then address them we shall.”

Whatever the outcome of the review, Davies warns against discounting the majority view of the scientific community, on the basis of unsubstantiated allegations about what one part of it did. “The bigger picture is that the sum total of scientific evidence for global warming largely as a result of human activity is overwhelming,” he emphasised.

Friday Round-Up: Met Office tangles with Russian group on temperature rises

The Met Office's data (in the top figure) has been backed up by the European Centre for Medium-Range Weather Forecasting, whose data uses "all available observations" (in the bottom figure) and indicates that the Met Office average warming record is at the lower end of the likely range.

If you were working out the temperature of the planet, would you use every single measurement you could get your hands on, even if there was the chance that some of the thermometers used were broken? Or would you use a smaller, more reliable set of information? And if you had to take advice in making the choice, would you take it from an accountant or a weatherman?

Those are the kind of questions raised by a January 7 statement from the Moscow-based Institute of Economic Analysis, which claims that the UK’s Met Office’s “calculations of global temperature do not meet basic scientific standards”. The accusation stems from the meteorologists’ efforts to clear themselves of another charge made by the IEA in December that it “had probably tampered with Russian climate data”. The Russian economists’ latest claim particularly picks on the Met Office’s explanation that it does not use all available data, instead selecting data that it feels it can trust. Clearly this is shaky ground – surely it must be tempting to pick the results that agree with your outlook? But then steps must also be taken to ensure your information is accurate.

The IEA originally released a statement calling into question a set of data known as HadCRUT during the Copenhagen summit, on December 16. That strange name combines the two institutions involved, the Met Office’s Hadley Centre and the Climatic Research Unit (CRU) at the University of East Anglia. You might recognise the CRU as the source of the leaked emails recently at the centre of the “Climategate” scandal. Following suggestions arising from those emails that the CRU was making false claims about global warming, the Met Office had released the HadCRUT information for all to see on December 8. Yet instead of calming the issue, this just led to the IEA accusation that the Met Office selected which data to use in the model, so it could exaggerate the evidence behind global warming.

Next, the Met Office highlighted an independent analysis by the European Centre for Medium-Range Weather Forecasts (ECMWF) into a wide range of temperature data, including the HadCRUT figures. The study looked into worldwide temperature rises since 1989, and the picture at the top of the entry shows the outcome. The top map is from the HadCRUT measurements and the bottom map is what’s used for the ECMWF analysis. The Met Office’s statement says that the ECMWF estimates temperature rises to be even greater than the HadCRUT measurements had.

While the conclusions are fairly clear, the lack of detail provided makes me feel like science is the loser in all of this. The Met Office seems to have rushed this statement out, and a spokesperson I talked to briefly earlier said that she did not think the ECMWF study had yet been published in full. As an institution trying to communicate the threat of global warming, the Met Office clearly feels that it must show why the accusations from Russia are wrong. Given that the think tank has no particular scientific qualifications of its own, having been founded by a climate sceptic former advisor to Vladimir Putin, perhaps a simple press release will be enough to do that. Nevertheless, if this is supposed to seriously reinforce the credibility of global warming, the data must be made more widely available.

Perhaps the most bizarre part of the whole episode, which makes me suspect that the IEA is detached from reality, is its conclusions from the Met Office’s responses to it original report. It says:

“The British Met Office’s statements are consistent with some of the main conclusions of the IEA’s report: the use of data by its researchers in the calculations of global temperature do not meet basic scientific standards and therefore the resulting temperature measure – an increase in the global temperature by 0.74°С – turns out to be unreliable.”

The Met Office agrees with the IEA conclusion that the HadCRUT data is flawed? It seems unlikely, and indeed a quote used to justify this comment also shows the pains taken to make accurate measurements.

I have asked the Met Office to look into whether the ECMWF study will be published at all, but because of an aptly-timed spell of freezing weather in the UK its representatives are “snowed under”. I hope to ask them a few questions anyway and if I get a response, I’ll post it separately.

Damn, that’s not as simple as I’d hoped. In other news, the University of Alaska has published a paper in the journal Arctic saying that over a similar time period to the ECMWF study, polar bears are spending more time on land and in water than on ice, largely due to the absence of ice. I hope that future Friday round-ups will be shorter and simpler.