Melting ice makes the Arctic a vicious circle

DEBORAH SMITH

The Age, April 29, 2010

http://www.theage.com.au/environment/climate-change/melting-ice-makes-the-arctic-a-vicious-circle-20100429-tssb.html

Nature abstract available at - http://www.nature.com/nature/journal/v464/n7293/pdf/nature09051.pdf

EVERYONE knows how much hotter it feels to wear a black T-shirt, rather than a white one, on a warm day.

In the same way, the melting of sea ice in the Arctic, revealing the dark water below, has been shown by Australian scientists to be the main cause of unusually rapid warming at the top of the world.

Confirmation of this "feedback loop" means the region is likely to continue to warm strongly, with greater loss of sea ice and possible melting of the ice sheets.

James Screen and Ian Simmonds, of the University of Melbourne, said the rise in surface temperatures in the Arctic in the past 20 years had been more than double the global average.

The reasons for this enhanced warming have been "hotly debated" by scientists, with factors such as changes in cloud cover, and ocean and atmospheric circulation suggested as playing a role, along with sea ice loss, Dr Screen said.

To test these ideas, the researchers looked at the latest detailed atmospheric information, modelling and satellite measurements, including warming at different heights from the surface, for the period 1989 to 2008.

"Arctic warming is strongest at the surface during most of the year and is primarily consistent with reductions in sea ice cover," said Dr Screen, whose study is published in the journal Nature.

Cloud cover did not have a big effect on recent warming, although increases in water vapour may have an impact in the lower part of the atmosphere in summer and early autumn.

Dr Screen said white ice reflects a lot of sunlight, but as it melts due to man-made warming from greenhouse gas emissions, the dark water that is exposed absorbs more heat, which in turn, melts more ice, and so on.

The amount of Arctic sea ice was at a record low in the summer of 2007, down about 40 per cent.

Although it has recovered slightly since, the long-term trend is down, he said. "We're heading towards a situation where the Arctic Sea will be ice-free in summer."

US research paper questions viability of carbon capture and storage

Document from Houston University claims governments overestimated CCS value

Terry Macalister 

guardian.co.uk, Sunday 25 April 2010

http://www.guardian.co.uk/business/2010/apr/25/research-viabilty-carbon-capture-storage

A new research paper from American academics is threatening to blow a hole in growing political support for carbon capture and storage as a weapon in the fight against global warming.

The document from Houston University claims that governments wanting to use CCS have overestimated its value and says it would take a reservoir the size of a small US state to hold the CO2 produced by one power station.

Previous modelling has hugely underestimated the space needed to store CO2 because it was based on the "totally erroneous" premise that the pressure feeding the carbon into the rock structures would be constant, argues Michael Economides, professor of chemical engineering at Houston, and his co-author Christene Ehlig-Economides, professor of energy engineering at Texas A&M University

"It is like putting a bicycle pump up against a wall. It would be hard to inject CO2 into a closed system without eventually producing so much pressure that it fractured the rock and allowed the carbon to migrate to other zones and possibly escape to the surface," Economides said.

The paper concludes that CCS "is not a practical means to provide any substantive reduction in CO2 emissions, although it has been repeatedly presented as such by others."

The report has come at a critical time when British and other governments worldwide have started to fast-track a series of CCS prototype schemes as a way of removing carbon from the atmosphere and helping with climate change.

On 8 April, Royal assent was given on to what is now the Energy Act 2010, which made law plans to raise a levy on power users to establish four CCS projects in Britain. Ministers see this as a potentially planet-friendly way of building new coal fired power stations, such as the one E.ON wants to construct at Kingsnorth, in Kent.

The Carbon Capture and Storage Association (CCSA), which lobbies on behalf of the sector, says Britain is now at the forefront of new technology with a legislative framework in place that offers the opportunity for long-term investment.

Projects are proceeding in the US, such as the experimental coal-fired Mountaineer plant in New Haven, West Virginia, which began small-scale carbon capture last year, as well as in Canada, China and other countries.

Jeff Chapman, chief executive of the CCSA, believes Economides has made inappropriate assumptions about the science and geology. He believes the conclusions in the paper are wrong and says his views are backed up by rebuttals from the Lawrence Berkeley National Laboratory, the Pacific Northwest National laboratory and the American Petroleum Institute.

The British Geological Survey confirmed it was looking at the Economides findings and was hoping to shortly produce a peer-reviewed analysis.

Economides, who has a PHD from Stanford University, said he had seen the arguments against his paper from the API and dismissed them as "nonsense" saying vested interests are protecting a new concept foisted on the world by geologists without proper thought.

"I was a [practising] petroleum engineer for many years and soon realised that geologists did not understand flow and the laws of physics, against which you can't argue."

Chapman pointed out that Statoil, a Norwegian oil company, had been injecting CO2 into an old reservoir on the North Sea Sleipner field for some time as a successful experiment in carbon storage. But Economides says the Sleipner scheme involved a million tonnes over three years, while one 500mW commercial station would need to absorb and store 3m tonnes annually for 25 years.Economides, who admits he veers towards being something of a climate change sceptic, says the oil and coal industries see these schemes as potential solutions so they can keep on doing what they have been doing in the past, but "CCS is the last refuge of the scoundrel," he said.

Emissions changing ocean balance

WASHINGTON

The Age, April 24, 2010http://www.theage.com.au/environment/emissions-changing-ocean-balance-20100423-tjco.htmlThe report is available for download here - http://www.nationalacademies.org/morenews/20100422.html

THE chemistry of the oceans is changing faster than it has in many thousands of years because of the carbon dioxide being absorbed from the atmosphere.

The finding comes in a report from the US National Research Council.

Carbon dioxide and other industrial gases in the air raise global temperatures in the greenhouse effect.

One factor easing that warmth has been the amount of CO2 taken up by the oceans, but that makes the water more acidic, which can affect sea life.

Since the Industrial Revolution in the 18th century, the pH of ocean water has declined from 8.2 to 8.1 and a further decline of 0.2 to 0.3 units is expected by the end of this century, according to the council, an arm of the National Academy of Science.

The current rate of change ''exceeds any known change in ocean chemistry for at least 800,000 years'', the report said.

The pH level is a measure of how alkaline or acidic something is. A pH of 7 is neutral, while higher numbers are more alkaline and lower numbers more acidic.

As the ocean becomes more acidic scientists have raised concern about dissolving coral reefs and potential effects on fish and other sea life.

The US government has developed the National Ocean Acidification Program, which has called for a 10-year strategic plan and states have been asked to consider options.

AP

Scientists call for research on climate link to geological hazards

Experts say suggestions that climate change could trigger more volcanoes and earthquakes are speculative, but there is enough evidence to take the threat seriously

David Adam, environment correspondent 

guardian.co.uk, Monday 19 April 2010

http://www.guardian.co.uk/environment/2010/apr/19/climate-change-geological-hazards

Scientists today called for wide-ranging research into whether more volcanoes, earthquakes, landslides and tsunamis could be triggered by rising global temperatures under global warming.

Significant warming of the atmosphere in the distant past can be linked to changes in geological activity, they say. Suggestions that climate change predicted for coming decades could bring similar changes remain speculative, but the scientists say there is enough evidence to take the threat seriously. Some experts have already linked current levels of global warming to rockfalls and landslides in mountain regions.

Richard Betts, a climate modeller at the Met Office Hadley Centre in Exeter, said: "This is a new area of academic research with potentially interesting implications. It was previously assumed there was no link at all between climate change and these events, but it is possible to speculate that climate change might make some more likely. If we do get large amounts of climate change in the long term then we might see some impacts."

He said there was no evidence that current levels of global warming were influencing events such as last week's earthquake in China that killed hundreds of people and the volcanic eruption in Iceland that grounded flights across Europe.

Experts say global warming could affect geological hazards such as earthquakes because of the way it can move large amounts of mass around on the Earth's surface. Melting glaciers and rising sea levels shift the distribution of huge amounts of water, which release and increase pressures through the ground.

These pressure changes could make ruptures and seismic shifts more likely. Research from Germany suggests that the Earth's crust can sometimes be so close to failure that tiny changes in surface pressure brought on my heavy rain can trigger quakes. Tropical storms, snowfall and shifting tides have all been linked to shifts in seismic activity.

Writing in a special series of scientific papers on the topic published today by the Royal Society, Bill McGuire, head of the Benfield Hazard Research Centre at University College London, says: "In relation to anthropogenic climate change, modelling studies and projection of current trends point towards increased risk in relation to a spectrum of geological and geomorphological hazards in a warmer world, while observations suggest that the ongoing rise in global average temperatures may already be eliciting a hazardous response from the geosphere."

He adds: "In order to improve knowledge and reduce uncertainty, a programme of focused research is advocated ... The IPCC [Intergovernmental Panel on Climate Change] is also strongly exhorted to address more explicitly in future assessments the impact of anthropogenic climate change on the geosphere, together with its manifold potentially hazardous consequences."

The papers follow a special meeting on the subject last year and are published in the journal Philosophical Transactions of the Royal Society A. They include studies of the likely impact of rising temperatures on events such as earthquakes and volcanoes, as well as whether the release of gas from undersea deposits called gas hydrates could trigger landslides and tsunamis.

McGuire says: "No increase in the global incidence of either volcanic activity or seismicity has been identified to date ... It may be the case that modulation of potentially hazardous geological processes due to anthropogenic climate change proves too small a signal to extract from the background noise of normal geophysical activity, at least in the short to medium term."

Frogspawn study reveals climate change dangers

By Emily Beament, PA

Tuesday, 20 April 2010

http://www.independent.co.uk/environment/climate-change/frogspawn-study-reveals-climate-change-dangers-1949040.html

A study of thousands of records of when UK frogs spawn revealed the amphibians are closely adapted to local conditions - which could put them at risk as the climate changes.

More than 50,000 records of frogspawn, including contributions from the public and BBC Springwatch viewers, were used to see how common frogs responded to temperature across different parts of the UK.

Frogs spawn earlier in warmer years, which provides a longer period for tadpoles to develop, potentially reducing competition for food, and may reduce the chances of the offspring being eaten by newts.

Frogs in the warmer South West lay their spawn earlier on average than those in the colder north and east.

But the records from between 1998 and 2006 found that while all populations of frogs spawned earlier in warmer springs, those in the south do so several days earlier than northern frogs - even if they are experiencing the same temperatures on the same days.

The researchers, writing in a paper published in the Proceedings of the National Academy of Sciences, said the findings showed the frogs were genetically adapted to their local climatic conditions.

For example, frogs in more northern parts of the UK may not respond as quickly to a warmer spring as they are more likely to experience a cold snap, which would kill the spawn, than the south.

But because frogs are so adapted to their immediate environment they will not be able to deal with the changes in the local climate that global warming will bring, conservationists warned.

And the Woodland Trust, which manages the Nature's Calendar survey of observations from which the 50,000 records were drawn, said a wide range of UK wildlife could be facing the same problem.

The results indicate frogs have sufficient flexibility to respond to warmer temperatures by spawning up to seven days earlier on average.

But they would need to spawn on average 30 days earlier by the second half of this century to keep in step with predicted changes in temperature of up to 3C in the South East and 1.7C in the North West between 2050 and 2070.

The shortfall between their ability to bring forward their spawning time and the shift required by rising temperatures could be as much as 25 days in the south of the UK, the study said.

As a result frogs will have to evolve, which is unlikely given the short timescale over which temperatures are rising, or move north to find suitable conditions.

One of the paper's lead authors, Albert Phillimore from Imperial College London, said: "It is unlikely that frogs will be able to evolve sufficiently rapidly, so they will need to move northwards.

"All frog populations face a challenge but the most southerly populations are in the greatest predicament because the English Channel provides a total barrier to immigration from further south."

And Richard Smithers, senior conservation adviser for the Woodland Trust, said: "The average climate frogs will experience in their local environment will be quite different from that they are experiencing today - it will be like a climate from a lot further south."

He said frogs would need to move north to find conditions closer to what they are used to.

But he said: "To do that they have a huge challenge. Frogs are not good at dispersing and we have a really hostile landscape for wildlife so they will struggle to get there.

"This reinforces the message that conservationists are saying loudly at the moment - that we need to create landscapes which work for wildlife as well as people, across which wildlife can move and which at the same time produce the food we need."

'Tiny' climate changes may trigger quakes

By Emily Beament, PA

The Independent, Monday, 19 April 2010

http://www.independent.co.uk/environment/climate-change/tiny-climate-changes-may-trigger-quakes-1948432.html

Climate change could spark more "hazardous" geological events such as volcanoes, earthquakes and landslides, scientists warned today.

In papers published by the Royal Society, researchers warned that melting ice, sea level rises and even increasingly heavy storms and rainfall - predicted consequences of rising temperatures - could affect the Earth's crust.

Even small changes in the environment could trigger activity such as earthquakes and tsunamis.

And some evidence suggests the consequences of climate change were already having an impact on geological activity in places such as Alaska, researchers writing in the journal the Philosophical Transactions of the Royal Society A said.

Bill McGuire, of the Aon Benfield UCL Hazard Research Centre at University College London, and the author of a review in the journal of research in the area, said warming temperatures melted ice from ice sheets and glaciers and increased the amount of water in the oceans.

As the land "rebounds" back up once the weight of the ice has been removed - which could be by as much as a kilometre in places such as Greenland and Antarctica - then if, in the worst case scenario, all the ice were to melt - it could trigger earthquakes.

The increase in seismic activity could, in turn, cause underwater landslides that spark tsunamis.

A potential additional risk is from "ice-quakes" generated when the ice sheets break up, causing tsunamis which could threaten places such as New Zealand, Newfoundland in Canada and Chile.

The reduction in the ice could also stimulate volcanic eruptions, according to the research.

And the greater weight of the water in the oceans where sea level has risen as ice melts can "bend" the Earth's crust. This produces magma and causes volcanic and seismic activity in coastal or island areas - where the majority of 550 volcanoes whose eruptions have been historically documented are found.

Increased volcanic activity could cause more landslides, and have impacts well beyond the area where the volcano is situated - for example by releasing sulphur clouds into the atmosphere or by affecting air travel.

Prof McGuire said the changes could occur in the coming decades or over centuries, rather than thousands of years, depending on factors such as how quickly sea levels rose.

And he warned: "The rise you may need may be much smaller than we expect. Looking ahead at climate change, we may not need massive changes.

"One of the worries is that tiny environmental changes could have these effects."

His review said there was "mounting evidence" of seismic, volcanic and landslide activity being triggered or affected by small changes in the environment - even specific weather events such as typhoons or torrential rain.

Prof McGuire said that in Taiwan the lower air pressure generated by typhoons was enough to "unload" the crust by a small amount and trigger earthquakes.

Other impacts of rising temperatures include glacial lakes bursting out through rock dams and causing flash flooding in mountain regions such as the Himalayas, as well as rock, ice and landslides as permafrost melts.

And he said there may be "tipping points" in the geological systems, where the crust reaches a threshold that causes a step-change in the frequency of such events - but it was not clear where those thresholds might lie.

At times in the past climate change has been seen to have links with enhanced levels of potentially hazardous geological activity - for example after the end of the last ice age.

But they have not been fully considered as potential impacts of the rapid changes in the climate expected in the future and there was a great deal of uncertainty about what might happen in coming years.

Prof McGuire called for a programme of research focusing on the potential geological hazards that global warming could bring, with the leading body on global warming, the Intergovernmental Panel on Climate Change (IPCC), addressing the issue directly in its future assessments.

Whale poo key to healthy oceans

ANDREW DARBY

The Age, April 23, 2010http://www.theage.com.au/environment/whale-poo-key-to-healthy-oceans-20100422-tfvc.html

EVERY little bit helps. Research has revealed the potential value of whale poo in mitigating climate change through its recycling of iron.

Australian Antarctic scientists looking into ways to increase the amount of CO2-absorbing algae in oceans have traced the passage of iron through whale digestive systems and have found that whales take up iron when they consume shrimp-like krill.

Before commercial whaling began early last century, whales consumed about 190 million tonnes of krill per year, converting this into about 7600 tonnes of iron-rich faeces, which encouraged the growth of carbon-absorbing algae, according to Steve Nicol, of the Australian Antarctic Division.

''This monumental fertilising effort means the whales may have been responsible for recycling about 12 per cent of the current iron content in the surface layer of the Southern Ocean,'' Dr Nicol said.

''The baleen whales' faecal iron concentration is about 10 million times that of Antarctic seawater.''

He said about 24 per cent of the total iron in the Southern Ocean surface water is currently stored within krill body tissue.

''The most recent estimates of krill biomass in the Southern Ocean is 379 million tonnes, storing about 15,000 tonnes of iron.''

The research suggests increasing populations of baleen whales and krill would have a positive effect on the Southern Ocean ecosystem and improve the ocean's ability to absorb CO2.

$20bn emissions compo 'a waste'

ADAM MORTON

The Age, April 22, 2010http://www.theage.com.au/environment/20bn-emissions-compo-a-waste-20100421-szzv.htmlDownload the report here - http://www.grattan.edu.au/pub_page/report_energy1.html

MORE than $20 billion would be wasted on unwarranted compensation to polluting sectors under the Rudd government's proposed emissions trading scheme, a damning analysis has found.

The analysis by think tank the Grattan Institute - the first to examine the financial reports of major businesses in line for compensation - found only the steel and cement sectors could make a case for taxpayer help. Others that compete overseas, including alumina refining, LNG production and coalmining, would be marginally less profitable, but not forced to close.

Aluminium smelting is in another category - it would become unprofitable, but the analysis found the government should let it move offshore.

Many overseas aluminium plants run on comparatively environmentally friendly fuel and emit less greenhouse gas than an Australian smelter. Help would go directly to the communities and workers that would feel the brunt of the closure, such as Portland in Victoria, and not companies such as Alcoa.

Despite opposition resistance to the emissions scheme in Canberra, the analysis assumes a carbon price is inevitable, reflecting international trends.

Grattan Institute chief executive John Daley said fears about big job losses and cost increases were not supported by evidence and led to irrational policy.

Mr Daley said emissions trading would have a smaller impact on lives than predicted.

It involved less structural adjustment than the end of tariff protection and would increase the cost of living less than the GST.

The trade-exposed sectors examined bring in 8 per cent of the gross domestic product and are responsible for about 30 per cent of emissions. They employ 70,000 people. The analysis found most of these jobs would be viable under a carbon price without compensation. By comparison, 55,000 jobs were lost in the vehicle sector between 1973 and 1995 and 64,000 in textiles, clothing and footwear manufacturing in the two decades to 2005.

The analysis noted that 176,000 jobs had been lost in the power sector due to privatisation and competition reforms. About 9000 people are employed in electricity generation - the only part of the sector that would be affected by the scheme.

The institute found the free permits cost the taxpayer $65,000 per employee working in trade-exposed sectors. In aluminium smelting, it is $160,000 an employee.

Mr Daley said free permits were an exemption from a tax paid by the rest of the community. He preferred a carbon border tax for imports in the few sectors under threat to bring their carbon price into line with the national figure.

The analysis said giving free carbon permits would delay reform. Given as proposed, no polluting, internationally trading facility would close.

It assumes a target of cutting emissions 5 per cent below 2000 levels by 2020. A more ambitious target in the government's 5-to-25 per cent range would require more countries to take on a carbon price, making the impact on trade-exposed sectors less of a concern.

Climate change programs lack credibility: audit

LENORE TAYLOR NATIONAL AFFAIRS CORRESPONDENT

The Age, April 21, 2010http://www.theage.com.au/environment/climate-change-programs-lack-credibility-audit-20100420-sru2.htmlDownload Audit Report 27 here - http://www.anao.gov.au/director/publications/auditreports/2009-2010.cfm

THE federal government could provide ''no documentation'' on how it assessed the $4.45 billion ''clean energy initiative'' announced in last year's budget, according to an audit report detailing a litany of failures in both Howard and Rudd government greenhouse programs.

''There was no documentation held by the department relating to … advice on the costs and benefits of the proposal and the management of risks associated with implementing the program,'' the audit found.

In another report the Audit Office reveals that federal and state governments have revised down by 15 per cent the amount of greenhouse gas abatement their policies will achieve by 2012.

A spokesman for the Resources Minister, Martin Ferguson, whose department administers the clean energy initiative, said, ''The department developed its policy advice using a large body of pre-existing documentation on carbon capture and storage'' - the technology for which more than half the clean energy money is earmarked.

The harsh assessment of Australia's climate change programs comes as a meeting of ministers from the world's major greenhouse gas emitters failed to agree how global climate talks should proceed after the failure of last year's UN meeting in Copenhagen, and downplayed the chances of reaching a deal at this year's talks in Mexico.

The Climate Change Minister, Penny Wong, said she believed the Copenhagen accord - the political agreement thrashed out in the Danish capital last December - was ''the best international consensus to date and the key to getting international action on climate change''.

But the Major Economies Forum meeting she has been attending in Washington was downbeat and the US climate envoy, Todd Stern, said afterwards that agreement in Mexico in December might not be possible.

The audit report was also scathing about the greenhouse gas abatement program set up under the Howard government and continued in the early years of the Rudd government, a competitive grants program similar to Tony Abbott's planned ''direct action'' climate change scheme. A previous audit had criticised the first two rounds of the scheme, but yesterday's report found the third round was not any better.

The three projects funded were ''technically ineligible'' because they did not meet the criteria, only one produced any greenhouse abatement at all, and even that project only reduced emissions by a third of the amount it had promised.

The Greens senator Christine Milne said the report ''should give Tony Abbott and [the opposition climate spokesman] Greg Hunt pause for thought''.

''Clearly the approach they have taken is not an effective or efficient way of delivering emissions cuts. We know we need to do a lot more than throw a few grants around if we are to stimulate the huge growth in green technologies we need," she said.

The report also criticised the original rebate scheme for solar roof panels, saying it achieved greenhouse gas abatement at a cost of about $447 each tonne of carbon, compared with the estimated costs in the early years of an emissions trading scheme of about $20 or $30 a tonne.

It also found that the impact of federal and state government measures had caused their greenhouse gas abatement impact to be revised down by 15 per cent over the past two years.

Scientists cleared of malpractice in UEA's hacked emails inquiry

 Researchers 'dedicated if slightly disorganised', but basic science was fair, finds inquiry commissioned by university

David Adam, evironment correspondent 

guardian.co.uk, Wednesday 14 April 2010

http://www.guardian.co.uk/environment/2010/apr/14/oxburgh-uea-cleared-malpractice

The climate scientists at the centre of a media storm over emails released on the internet were disorganised but did not fudge their results, an independent inquiry into the affair reported today.

The inquiry, the second of three set up in the wake of the controversy, found "absolutely no evidence of any impropriety whatsoever", according to Lord Oxburgh, who led the investigation.

Instead, Oxburgh said, many of the criticisms and assertions of scientific misconduct were likely made by people "who do not like the implications of some the conclusions" reached by the climate experts.

He said the allegations made against the scientists at the Climatic Research Unit at the University of East Anglia, including its director Phil Jones, were serious enough to end their careers if proven correct.

Oxburgh said: "Whatever was said in the emails, the basic science seems to have been done fairly and properly."

The review gave scientific processes at CRU "a clean bill of health" but did raise some issues of concern. Record-keeping was patchy, it said, while the scientists did not use the best possible statistical techniques to analyse their data.

David Hand, a statistician at Imperial College London, who sat on the enquiry panel, said the CRU scientists had been naive over their use of statistics, but there was no evidence that the better techniques would have produced different results. Poor record-keeping was common among scientists, Oxburgh said, while the CRU experts could not have anticipated the future public interest in what had been an "unfashionable" area of science for much of their careers.

The review analysed 11 key scientific papers produced by the CRU scientists over the last 20 years, which included key findings on global warming used in several reports from the Intergovernmental Panel on Climate Change (IPCC).

Oxburgh said the scientific papers contained the necessary caveats and expressions of uncertainty where required. But he criticised the way these caveats were often stripped away when such research was presented by other bodies, such as the media, government agencies and the IPCC.

Oxburgh singled out a graph of global temperature used in a 1999 report for the World Meteorological Association, which spliced three different data sets, as an "unfortunate representation of a very complex piece of science". The graph was prepared by CRU experts, and was the subject of the infamous email from Jones in which he described how he had used a "trick" to "hide the decline". Jones said the relevant error ranges were included in the WMO document.

At a press conference to launch the review's findings, Hand re-ignited a long-standing row about a high-profile study published in 1998 by scientists led by Michael Mann at Penn State University, US. The paper featured an emblematic graph known as the "hockey-stick" that showed temperature rise in the twentieth century was unprecedented in recent history. Hand said the study gave him an "uneasy feeling" because it used "inappropriate statistical tools". The hockey-stick effect was genuine, Hand said, but the 1998 paper exaggerated it. He praised Steve McIntyre, a Canadian climate blogger who led much of the criticism of the CRU scientists, for identifying the problem.

Mann told the Guardian that the 1998 study had been approved by the US National Academy of Science and Hand had offered a "rogue opinion" that "should not be given much attention or credence".

Oxburgh said sustained requests to CRU scientists for data and computer codes from McIntyre and others could have amounted to a campaign of harassment, and that the affair left several unresolved questions about how Freedom of Information laws should be applied in an academic context.

The report also said it was "unfortunate" that the UK government had introduced widely copied policies to charge for environmental data sets, such as those used by the CRU scientists and requested by critics. The move impeded the flow of data between researchers, it added.

The Oxburgh review follows a report on the CRU emails last month from the Commons Science and Technology Select Committee, which also cleared the scientists involved of wrongdoing. A third enquiry, led by Sir Muir Russell, is due to report next month.