The Last Great Global Warming

Sat, 12 Dec 2009 17:12:40 +0000

As world leaders gather in the Danish capital Copenhagen to negotiate a successor to the Kyoto Agreement, it’s probably worth pondering on what happened last time temperatures were at levels predicted for the end of this century.

In 1874, a scientist called Pieter Harting took a number of cores that had been taken around the Dutch city of Amersfoort. The sediments they contained provided a treasure trove of information on an ancient climate. Not only did the ocean muds Harting find show this part of the Netherlands was once under the sea but the seashells contained therein belonged to species that did not live in the 19th century North Sea. Crucially, some of his fossil species were identical to those living in the Mediterranean, suggesting that the North Sea had been warmer than today. He named the layers ‘Système Eémien’ after the River Eem that flowed alongside Amersfoort. We now know these layers date back to between 130,000 and 116,000 years ago. Although this sounds like an interminably long time ago, it was yesterday as far as our planet is concerned and was a period of low ice volume; a time when ice sheets were smaller than today. Could this be a vision of the future?

There’s no doubt it was warm at this time. Eemian Britain, for instance, had a menagerie of hippos, elephants, rhinos and hyenas that roamed the island. It looked more like the African savannah than the rain-sodden landscape we’d recognize today. Fossil bones of these creatures have been found as far north as Yorkshire, with some of the best evidence discovered under London’s Trafalgar Square. Their presence might suggest that it was blisteringly hot, but it’s not as clear-cut as that. Although we might associate this wildlife with today’s Africa, these beasties have often happily inhabited Britain during interglacials. The Eemian was no exception. There is no evidence for people at the same time, suggesting that our ancestors’ absence from Britain allowed these exotic animals to prosper. As a result, their presence is not a great indicator of temperature. It tells us it was warm, but by how much?

Fortunately we have an Arctic goldmine of climate data in the Greenland Ice Sheet. Even today, the dimensions of this icy preserve are staggering. Outside of Antarctica, half of all the freshwater in the world is locked up in Greenland. Of the 2.2 million square kilometres that make up this island, 85% is covered in ice. The highest point – known as Summit – is nearly 3.3 kilometres above sea level, while the sheet itself measures 2500 kilometres north to south. Ice cores taken from here can be more than 3 kilometres long, stretch back 123,000 years and allow exquisitely detailed reconstructions year by year. It’s probably the closest thing climate researchers have to holy ground.

Appropriately for the climate negotiations, much of the key findings on Greenland has been led by University of Copenhagen researchers working on kilometres of ice stored within huge walk-in freezers set to a frigid -20˚C. Early work recognised that in the central and north Greenland cores, the Eemian ice layers had a heavier isotopic makeup than snow falling in the same areas today. The size of this difference meant that if the signal was converted to temperature the Eemian was some 5 °C warmer than now. Not only this, but the southern part of Greenland appears to have had little or no ice at this time. It all points to the Arctic being a lot warmer during the Eemian than in the late 20th century.

We know that because of the Earth’s changing orbit, the Arctic received a lot more heat from the Sun during spring and summer. As the surface of the ice melted, the overall height of the ice sheet would have dropped, exposing it to the warmer temperatures of lower altitudes, and exaggerating the melting further. If this wasn’t enough, as temperatures increased around the world, natural processes released ancient carbon stored in the soils and oceans of the world, warming the planet further by enhancing the greenhouse effect. This rise in temperature left an indelible mark on the surface of our planet, most notably along many of today’s coastlines. By investigating ancient beaches and corals dating back to this time we can see the world’s sea level was some 4 to 6 metres higher than present day. This is an ominous sign for the future.

The Eemian shows that if Arctic temperatures are allowed to rise above and beyond the much quoted global 2˚C target we could be in for a challenging time. Unlike warming, where the average hides a range of different trends, sea level is global and the changes will happen virtually instantaneously. Anyone living on the coast will see the effects: rich folks with their trendy beach huts and poor people living in their fishing villages. Sea level change will be the ultimate leveller.

The key question is just how long high temperatures need to be sustained over the poles before we start seeing a comparable rise in sea level. We’re still not sure but it’s clear from the Eemian that we can’t allow high temperatures to be the norm over the Arctic.

It’s going to be a challenging week for our leaders in Copenhagen. Good luck to them.

Playing the Futures Game

Fri, 6 Nov 2009 12:26:08 +0000

During moments of idleness I’ve often dreamt of seeing into the future. I have been known to ponder frivolously who’ll win a World Cup Final or the US Masters but other times it’s a lot more prosaic; what will happen with a new initiative at work? How should I respond to comments on a research paper? Shall we go for coffee? And so on. We all draw on as much knowledge as we can to answer these sort of questions, but there’s often moments when we need to make a decision quickly; where time is of the essence but we don’t have all the information we’d like. Fortunately, if we make the wrong choice and things don’t go to plan, it’s often possible to quickly change tack and redress the situation. Yet what happens when you have a global environmental issue which urgently needs a deal that can’t afford to be wrong? Next month, the United Nations faces just such a challenge. Negotiations are taking place in Copenhagen to thrash out a new climate deal to replace Kyoto with nations offering a dizzying range of offers to cut their greenhouse gas emissions. What best combination will work? If there was some way of rapidly seeing into the future it would mean policy-makers could make a more informed decision and get the best possible deal that will help solve the problem.

Having a speedy insight into the future climate effects of policy decisions looks like it’s just made a big step forward with new technology offered through Climate Interactive. Climate Interactive offers policy-makers a proverbial crystal ball to see what will happen under different greenhouse gas emission scenarios. The model is known in the business as ‘Climate Rapid Overview and Decision-support Simulator’ (or C-ROADS-CP for short) and is operated by Ventana Systems in the USA. Calibrated using the global climate model results reported by the Intergovernmental Panel on Climate Change (better known as the IPCC), C-ROADS-CP produces instant results on what effects future emission scenarios might have. If we are to avoid the most dangerous effects of climate change, the European Union and other nations have set a target to keep global temperatures from rising more than 2˚C since the onset of Western industrialisation. Assuming agreement can be made in Copenhagen, the big question is just how big a cut in emissions will be needed by everyone to keep the temperature low enough to hit this target. C-ROADS-CP is now being used by policy-makers around the world to answer this question and offers real-time answers during Copenhagen.

This is all well and good but C-ROADS-CP is principally for policy-makers. Excitingly, Climate Interactive also lets you assume the role of an international negotiator and see what the future might hold. You can sit at a computer with a cup of coffee (or something stronger if you like) and run a slimmed down version of the program called C-Learn, free of charge. You don’t have to be in Copenhagen behind closed doors. With C-Learn it’s possible to play with a whole range of different scenarios of your own devising. You can enter the changes in greenhouse gas emissions for developed and developing countries, the time over which you want nations to make their cuts, targets to reduce deforestation and increase sequestration from afforestation, and the target of carbon dioxide levels in the atmosphere. It’s fascinating to work with the system online and a great way for people to play out their ideas for what we should do.

You can quickly see which combination of proposals may work and those that haven’t a chance of making a meaningful difference. After entering your ideas for who should do what and when, the long-term effects pop out a short moment later. You get an instant insight into future greenhouse gas levels and what will happen to the world’s temperature. If you’re giving a presentation you can even save the images for a talk to show the results to a wider audience. I found it fascinating. Scientists are often accused of just raising problems but here is a wonderful example of where science and policy come together to offer a range of answers (albeit challenging ones).

As an example, below is a screen shot of a scenario where we pump out 500 per cent more greenhouse gases by 2050 relative to 2005 levels. It’s a worst case scenario where we carry on partying likes there’s no tomorrow. The result is a projected temperature rise of 4.6˚C by 2100 with a carbon dioxide level of 955 parts per million (remember, today we’re at 388 ppm). Not great.

Once you play with the different controls on C-Learn, it soon becomes painfully clear that the developed world need to drastically reduce emissions. No great surprise here but the scale of the cuts are an eye opener. Have a look at the second screen shot below. If we plug in an 80 per cent target reduction by 2050 (relative to 1990) for the developed world as proposed by the European Union, stabilise emissions by the developing world and balance the rate of deforestation against afforestation we get an increase in global temperature of 2.8˚C with a carbon dioxide level of 467 ppm. This still punches through the 2˚C target but we’re getting closer to where we want to be.

There’s a sobering message here but the fabulous thing about the website is that it gives an instant answer to what effects proposed emission reductions might mean in a practical sense. What goes on with negotiations no longer has to be behind closed doors. Anyone can have a play with the future and see what might happen before world leaders set out their plans.

Have a go and see what you think. We can all get a clearer view of what lies ahead.

A warning from the North

Wed, 23 Sep 2009 10:28:50 +0100

I’ve just returned from fieldwork in Svalbard, the island archipelago situated halfway between Norway and the North Pole. Straddling 81˚ to 74˚N, this near-pristine environment is a haven for researchers interested in Arctic environments. I’ve been extremely privileged to visit some beautiful places in the world but was blown away by Svalbard. The islands are a heady mix of mountains, ice and 24-hour summer daylight that was totally different to anything I had ever experienced before. I was there as part of a University of Exeter research team to look into the impacts of past climate change, funded by the Leverhulme Trust. For two weeks, we boated, trekked, dug and probed our way into Svalbard’s recent geological past. As the ice has retreated back from its maximum limits at the end of the last ice age, the land has risen out of the sea, exposing ancient landforms and sediments that preserve a fabulous record of what has happened in this part of the world over the past 20,000 years.

A key question scientific and political circles is what might happen in this region in the near future. Without a major effort to cut the level of carbon in the atmosphere, the Intergovernmental Panel on Climate Change (the IPCC) has warned the world could be up to 6.4˚C warmer by 2100. Disturbingly, we know from ancient archives that the high Arctic experiences a far greater change in temperature than the global average. The region already is suffering some of the earliest effects of human-induced climate change, many of which have been spectacular. In September 2007, the fabled 5000 kilometre long waterway known as the Northwest Passage opened up as a navigable route without the need for ships armed with ice breakers. For centuries, finding a path through the region had been the stuff of dreams. Celebrated endeavours have been made over centuries to find an opening between the north Atlantic and Pacific but most revolved around ships smashing their way through the ice, or in the case of some Victorian expeditions, resorting to cannibalism when all hope was lost. More success has been had along Russia’s northern shore – the so-called Northeast Passage – but the going was still tough. It’s been 130 years since the first successful navigation of the Northeast Passage when the Swedish steam barque Vega managed to make it’s way through this route, reaching Japan in September 1879 after a hard winter locked for ten months in the sea ice off the Siberian coast. Since the summer sea-ice low of 2007, ice coverage has fallen even further, opening up the Northeast Passage completely and allowing the North Pole to be circumnavigated in 2008 for the first time in recorded history. It’s not taken long for the commercial opportunities to be realised. This year, the first trading ships passed through the Northeast Passage, a worrying indication of what might come to be the norm. But why are such big changes experienced this far north?

The key reason for this is that although the amount of sea ice cover in the Arctic waxes and wanes through the year, temperatures have steadily risen through the second half of the twentieth century; on average by some 0.5 °C a decade. A recent paper led by Darrell Kaufman of the Northern Arizona University and published in the international journal Science has shown that this warming has happened against a backdrop of cooling temperatures over the past two millennia that was driven by the changing orbit of the Earth around the Sun which contrived to cool the Arctic. Importantly, Kaufman’s team found four of the warmest five decades over the last 2000 years was experienced between 1950 and 2000. The cause is increasing greenhouse gas levels in the atmosphere, disrupting the natural system and warming the region some 1.4˚C more than it would be if the natural cooling had been allowed to continue uninterrupted. The amounts involved may not sound much but the rising mercury has been instrumental in changing the nature of the sea ice across the Arctic.

During the hedonistic summers of the 1970s there used to be over 50 per cent ice cover in the Arctic, but by 2008 this had crashed to less than 30 percent. As the cover has dropped, so too has the thickness of ice. During the Cold War, UK and US military submarine missions in the Arctic would routinely direct their sonar towards the surface to work out whether they could punch through the surface in an emergency and launch a missile at Moscow. Much of the submarine data has now been released, providing a treasure trove of valuable data. Put together, the data show a disturbing trend: the ice is getting thinner and on average younger. In the 1980s over 20 per cent of the Arctic sea ice was at least six years old but by 2008 this had declined to just 6 per cent. The thinner the ice, the less likely it will survive through the summer and the harder it is for the subsequent winter to build ice levels back up at the surface. This all has big climatic implications beyond the Arctic. Because the sea ice is so reflective, around 90 per cent of the heat received from the sun at these latitudes goes back out to space, making this region a massive natural refrigerator that help keeps our planet cool. The problem is as the ice cover goes, the summer heat is absorbed by the ocean and rereleased back into the atmosphere later in the year when the next phase of sea ice is supposed to be forming; autumn temperatures are now a staggering 5˚C above normal for the region. As the oceans warm the overlying air, these temperatures start to reach far inland, melting areas of permanently frozen ground in the region. Year on year, these feedbacks become stronger, accelerating the loss of ice cover and increasing the warming over the region relative to the rest of the planet. As a result, recent Arctic warming is almost twice that the global average.

While we were in Svalbard, the United Nations Secretary-General, Ban Ki-moon, visited to learn more about the effects of climate change in the region. His stay raised the international profile of a fragile environment in a rapidly changing world and highlighted the genuine concern that momentum is slipping from getting a deal in Copenhagen later this year. The nations of the world are supposed to be meeting in Denmark in December to thrash out a new deal to replace the Kyoto Protocol which expires in 2012, with the aim of significantly cutting future greenhouse gas levels in the atmosphere. Unfortunately, the negotiations seem to be slowing down. A major stumbling block appears to be just how much the developed world will cut emissions and what expectations can be placed on developing countries growing their economies in the future.

To try to get things back on track for Denmark, Ban Ki-moon yesterday hosted a UN summit on climate change in New York in an attempt to get a firm commitment from world leaders to set clear targets for emission reductions. There were some encouraging signs from the developing world. China announced a major change in policy by declaring it would increase the use of non-fossil fuel energy sources to 15 per cent and aim to significantly reduce greenhouse gas emissions by 2020. Although a precise target was not given on just how much less would be put in the atmosphere, this was a major shift in stance for China which had publicly rejected calls to cut emissions. Just before the meeting, India announced it was looking to invest a massive US$19 billion in solar energy as part of a bigger policy move to cut emissions; a promising move for a country where each person emits a quarter of the world average of greenhouse gases. Whether the developed world can make the necessary cuts remains to be seen. Japan is one of the most hopeful, declaring in New York that by 2020 it will cut the amount of carbon gases it puts into the atmosphere by 25 per cent (relative to 1990); up from its previous position of just 8 per cent. President Obama has been a little more circumspect on actual targets but is at least signalling the United States is willing to take a lead role in forging a deal, a promising sign that the intransigence of the previous eight years has ended. Meanwhile, the European Union has committed to a target of 20 per cent carbon emission reductions by 2020 while British Prime Minister Gordon Brown has become the first world leader to declare he will go to Copenhagen to help achieve a deal and urged others to join him.

Will world leaders pull the iron out of the fire and get a deal? I do hope so. I love Svalbard and would hate it to become a property hotspot in a warming world.

A Changing Climate in Copenhagen

Wed, 18 Mar 2009 22:21:19 +0000

I’ve just returned from a major climate meeting in Copenhagen with a mixture of emotions. Attended by more then 2000 scientists, the aim was to pull together the very latest in climate change science since the Intergovernmental Panel on Climate Change (better known as the IPCC) made their 2007 Fourth Report on the past, present and future world’s climate. Although the IPCC Fourth Report was an impressive summary of the worrying state of climate, its conclusions were based on science that was published before 2005. Since then a staggering amount of new work has been generated. Given the pace of research and the speed at which change is happening on the ground, this was a fantastic meeting to catch up on the latest thinking. Regardless of whether you attended, you can watch many of the key lectures by going to the conference website. They’re a great resource for anyone interested in climate change.

In the IPCC report, a number of different economic scenarios are set out over the next century. These provide a range of different emission rates of greenhouse gases which are then fed into the global climate models. The scenarios range from a low-emission future where population growth is relatively slow and economic and environmental solutions are sorted out at a local level, through to the so-called ‘business-as-usual’ scenario, something akin to ‘let’s have a party as the ship goes down’. Because it takes some time before the extra heat trapped by the earth is given up to the atmosphere, the climate changes envisaged under these different scenarios are broadly similar over the next couple of decades. But after about 2050 the differences between these scenarios start to play out through the climate system. So much so that by the end of this century, the low emission scenarios predicts a temperature rise of around 1.8˚C relative to 1990 but the ‘business-as-usual’ suggests something on the order of 4˚C. The question posed at the recent Copenhagen was: are these projections consistent with the latest science?

Unfortunately not. Almost everything I heard pointed to rates of change that mapped on or above the trajectories that lead to high-level change. I don’t think I was alone in feeling the atmosphere was quite surreal. Top flight scientists seemed to almost nonchalantly describe the oceans becoming more acidic, species becoming extinct, long-term (mega-) droughts and massive sea level rises. Some of these impacts are already happening or will do so within the lifetime of many of those attending. There was a bizarre matter-of-factness about the grim news. I co-chaired one session on lessons from the past and we heard researcher after researcher describe changes that our planet hasn’t seen for millions of years.

The timing for the meeting was well chosen. At the end of this year, world leaders and their negotiators will meet in the same conference center in Copenhagen to thrash out a new deal to stabilize greenhouse gas levels after 2012 when the Kyoto Protocol expires. In spite of much that was said, there were some rays of hope. It’s clear that adaptation and mitigation are still possible. In the session I helped organize we heard of archaeological lessons where people around the world had faced similar changes (albeit on a local or regional scale) and managed to successfully negotiate the hurdles they faced. At a national level, we learnt how Denmark has driven down it’s greenhouse gas emissions by investing in renewables (some 13 per cent relative to 1990 levels) and in the process opened up a huge new market. Danish companies control a phenomenal one-third of the global wind market. There’s a big lesson here.

We have to remember we can change our ways. We don’t have to follow the path we’re on. We have the know-how to cut our emissions and get greenhouse gas levels down. As the climate changes, new ‘green’ industries are developing with increasing pace. Opportunities are opening up to develop energy independence and other endeavours. A more sustainable path is becoming possible. With real political leadership, there could be real hope. The time is right for change. Let’s grab it.

Fixing Carbon

Fri, 17 Oct 2008 08:55:31 +0100

As with all great stories it began with a potato. Longer ago than I care to admit, there was a time when I was a young and foolish teenager. Left at home on one of the rare occasions my parents went out, I got it into my thick skull to microwave a potato. Having no idea what to do, the timer was set to a shockingly high 40 minutes. The inevitable result was a dead microwave and a glowing black lump where the potato had once been. It was one of those painful experiences in life that one tries to forget but years later it opened up a line of thought. We need to get the amount of greenhouse gases in the atmosphere down, and fast. Could microwaving plant material help? Using patented technology, I’ve been working with a team to set up a new company called Carbonscape which is doing just that.

As many readers will know, technology now exists to capture carbon dioxide (CO2) direct from any major source that emits the offending gas. The crucial point is that the carbon dioxide can be captured and stored underground; an approach commonly referred to Carbon Capture and Storage (or CCS). This does sound rather wonderful but unfortunately there are still major problems. There are very real concerns that CCS may not be the environmental solution it’s cracked up to be: this technology only deals with greenhouse gas emissions produced by large single sources, such as power stations, while the captured gases that are supposedly stored have the potential of escaping back to the atmosphere. If this wasn’t enough, CCS won’t become commercially available for at least another decade and can only capture carbon dioxide being released in the future; it does nothing to claw back the CO2 that is already in the atmosphere.

Using photosynthesis, plants are remarkably efficient absorbers of carbon dioxide. One alternative approach is to utilise natural sinks for sequestering carbon. Forests are one possibility. The potential of the terrestrial biosphere is enormous. Consider the figures. Each year we emit 8 billion tonnes of carbon. In contrast, 120 billion tonnes of carbon are sucked out of the atmosphere each year by photosynthesis on land. Unfortunately for us, all of this is pretty much returned to the atmosphere through respiration and decomposition of plant material.

Fortunately, however, we know from scientific studies that charcoal can store carbon for thousands of years. Ancient fires preserved in archaeological sites, including those found with ancient human remains, show carbon can be stable for thousands of years. This is because charcoal is highly resistant to microbial breakdown. Once formed, the charcoal effectively keeps the carbon out of the atmosphere and ocean for virtually indefinite periods.

We’ve taken this idea a step further at Carbonscape. Developing an industrial-scale unit, we’re converting wood waste and other biomass into charcoal. Our proprietary industrial microwave technology means that in spite of the energy used during production, the carbon captured draws down significantly more carbon dioxide from the atmosphere than it produces. Each industrial-scale unit converts 40-50% of wood debris into charcoal; one tonne of carbon dioxide can be fixed as charcoal per day. By converting carbon in organic material to charcoal, it can be then put into the ground where it does the most good.

At Carbonscape we hope we’re adding a new commercial reason for reforestation. Once wood has been turned into charcoal, the cleared area can be replanted, allowing us to repeat the process when the plants have matured, effectively sucking yet more carbon dioxide out of the atmosphere. A great example is the USA: if the 200 million hectares of forest used for timber production were turned to charcoal instead, each crop rotation would help bring carbon dioxide levels down by some 10 parts per million. And it’s not just potatoes or wood that can be turned into charcoal: other organic material (even sewage) can be turned into a permanent carbon sink.

The possibilities for fixing carbon are truly enormous.