Fighting sea rise with mirrors and mock volcanoes

To fight sea level rise it might take pumping suphur dioxide emissions into the atmosphere equivalent to 1991's Mount Pinatubo eruption (shown here) every 18 months. Credit: USGS/Cascades Volcano Observatory

To fight sea level rise it might take pumping suphur dioxide emissions into the atmosphere equivalent to 1991's Mount Pinatubo eruption (shown here) every 18 months. Credit: USGS/Cascades Volcano Observatory

If CO2 emissions can’t be cut, simulating volcanoes could help the 150 million people across the world threatened by rising sea levels, scientists said this week. But the UK, Denmark and China-based researchers who reach these conclusions also warn such ‘geo-engineering’ measures could be dangerous in other ways. “Substituting geo-engineering for greenhouse gas emission control would be to burden future generations with enormous risk,” said Svetlana Jevrejeva of the UK’s National Oceanography Centre.

150 million people worldwide are thought to live within 1 metre of high tide, Jevrejeva’s team notes. In 2007, the Intergovernmental Panel on Climate Change (IPCC) estimated that by 2100 the sea level would rise by 0.18–0.59 metres. However, since then several researchers have suggested a rise of 1-1.5 metres would be more likely. Read the rest of this entry »

Struggling to adapt: Sea creatures – and humans?

George N. Somero, associate director of Stanford University’s Hopkins Marine Station Credit: Chris Patton

George N. Somero, associate director of Stanford University’s Hopkins Marine Station Credit: Chris Patton

Ongoing increases in global temperature are enough to significantly disturb individual species of sea creatures and change many ecosystems, warns George Somero. “The rate at which temperatures are rising is unprecedented and may out-strip the ability of the processes of adaptation to ‘keep up with’ warming,” he says.

As professor of marine sciences at Stanford University and associate director of Hopkins Marine Station, Somero has long emphasised the obvious impacts of global warming on ocean life. One such impact is the increased risk of local extinction faced by species that have adapted to these warmer conditions and that are reaching the upper limits of temperatures that they can survive in. “If no replacement populations or species are around, then ecosystems may lose important members,” he explains. “Invasive species with high tolerance of heat are likely to be more and more successful as temperatures go up.”

Speaking at an American Physiological Society conference earlier this month, Somero showed that porcelain crabs living in tropical regions face such a local extinction threat. While their relatives in cooler regions still appear able to adapt to further warming, those in warmer areas are reaching their temperature limits. “The crabs raise general issues, notably the higher susceptibility of the most warm-adapted members of a group of species to stress from further warming,” the marine scientist explained. “The most warm-adapted species are the most heat tolerant, but they’re also often right at the edge of their tolerance limits.” Read the rest of this entry »

Saturday round-up: Getting CO2 questions wrong

Changes in Net Primary Production (NPP, in green), a measure of the speed of the photosynthesis process is closely tied to the overall amount of CO2 in our atmosphere (red). For each rise in NPP, CO2 levels fell by a similar amount, and when NPP fell, CO2 rose. Credit: Maosheng Zhao and Steven Running

Changes in Net Primary Production (NPP, in green), a measure of the speed of the photosynthesis process is closely tied to the overall amount of CO2 in our atmosphere (red). For each rise in NPP, CO2 levels fell by a similar amount, and when NPP fell, CO2 rose. Credit: Maosheng Zhao and Steven Running

The blossoming hopes that plants will thrive as the world warms up have been pruned this week by measurements of how much CO2 is absorbed by species on land. Net primary productivity – which measures the speed of the photosynthesis process crucial to plants – fell by 1 percent from 2000-2009, researchers found this week. As photosynthesis turns solar energy, CO2 and water to sugar, oxygen and eventually plant tissue, it’s one way that the world keeps the greenhouse effect in check.

“We see this as a bit of a surprise, and potentially significant on a policy level,” explained Stephen Running from the University of Montana, Missoula. The surprise comes because a previous study had shown that between 1982 and 1999 net primary productivity (NPP) increased by 6 percent, which, Running explains, “suggested global warming might actually help plant growth around the world.” While 1 percent is only a small reverse in comparison to the earlier increase, it still means 550 million tonnes of carbon per year less are being taken into plants than at the beginning of the decade.

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Turbo-charged changes create climate roadkill

Jens Borken-Kleefeld, whose work on climate impacts on transport showed car transport creates more warming per passenger mile than flying in the long term. Credit: IIASA

Jens Borken-Kleefeld, whose work on climate impacts on transport showed car transport creates more warming per passenger mile than flying in the long term. Credit: IIASA

If there were to be a speed limit for climate change, humans might soon find their license to wander the globe revoked. That’s because, as Jens Borken-Kleefeld explains, how fast climate is changing can be be just as damaging as the size of the change. He notes that this is covered by the UN Framework Convention on Climate Change. This international agreement pledges to stabilize greenhouse gases in a time frame that will allow natural systems to adapt naturally to climate change.

“If you have a very quick change – as is actually happening today – lots of biosystems and habitats cannot adapt,” he explains. “They are at the verge of extinction. We could trigger some irreversible events, like switching off the Gulf Stream, or melting of the Arctic, which is as much linked to the level but more to the rate of change.”

Borken-Kleefeld is one member of a large team that has been studying people’s tendency to press down on their accelerator, and what this does to the pressure on the climate change pedal. In the journal Environmental Science and Technology they looked at how different modes of transport contribute to warming. While they found that in the long run aviation had less warming impact per passenger mile than driving, the International Institute for Applied Systems Analysis scientists explains that it’s not just the long run that matters. “We are acting on various timescales,” he said. Read the rest of this entry »

Saturday round-up: Choosing between food, fuel and forests

False-colour satellite image of humans moving into rainforest space in Brazil. The colours have been chosen to highlight the destruction of the rain forest: the dark green of the natural forest contrasts the pale green and pinks of levelled forest. Credit: NRSC Ltd / Science Photo Library

False-colour satellite image of humans moving into rainforest space in Brazil. The colours have been chosen to highlight the destruction of the rain forest: the dark green of the natural forest contrasts the pale green and pinks of levelled forest. Credit: NRSC Ltd / Science Photo Library

The natural world is under threat from a human pincer movement, Conservation International scientist Will Turner pointed out last week. As well as being impacted by human-caused climate change, natural systems are threatened by how people respond to that change, he emphasises. “Very little time has been taken to consider what our responses to climate change might do to the planet,” Turner said. Consequently, Turner teamed up with researchers at Princeton University and the University of Massachussetts to highlight what has happened already, and what may happen in the future.

“Renewable energy, for example, is integral to virtually every national or international strategy for curbing emissions, including plans to promote biofuels,” the team wrote in a Conservation Letters paper published online ahead of print. “However, rising U.S. ethanol production has been linked to losses of grassland habitats in the Conservation Reserve Program, while booming demand for palm oil, including for use as a biofuel, spurred the clearing of more than 28,000 km2 of Malaysia and Indonesia’s megadiverse forests from 1990 to 2005.” Read the rest of this entry »

Enough gas already?

The Chinese research vessel Xue Long that bore Wei-Jun Cai and his colleagues on their 2008 research mission. Credit: Yong Wang, State Ocean Administration of China - the Chinese Arctic and Antarctic Administration, Beijing, China.

The Chinese research vessel Xue Long that bore Wei-Jun Cai and his colleagues on their 2008 research mission. Credit: Yong Wang, State Ocean Administration of China - the Chinese Arctic and Antarctic Administration, Beijing, China.

When the ice covering the Arctic Ocean retreated to a record low in summer 2007, what remained held a revelation for Wei-Jun Cai. Aware that the re-shaped environment could affect levels of greenhouse gas CO2 in the atmosphere as well as be affected by it, the following summer the University of Georgia marine scientist embarked on a mission to study exactly how. Together with his co-workers aboard Chinese research vessel Xue Long – which means “Snow Dragon”Cai sought to discover just how much CO2 the uncovered water could absorb. “It was widely accepted in the scientific community that once the ice was removed, there would be a huge amount of CO2 going into the basin,” he explained.

Over 90 percent of the world’s CO2 is absorbed by the ocean. The first step in that process is simply dissolving the gas in the water in a similar way to, but in lower amounts than, it would be in a fizzy drink. Algae living in the water can then breathe in the CO2, like any plant does, bringing the amount of the gas in the ocean back down. As the algae grows, feeding on other nutrients as it does so, the carbon stays locked within its cells. “In the Arctic, in the marginal areas, we have nutrients coming in from the Pacific, so that promotes biological fixation into algae,” Cai explained. “Previously, people only measured the ocean margin areas, and the Arctic basin when it was completely covered by ice. In those cases, you see very low CO2 levels in the ocean margins, and that’s still the same, we measured very low CO2 levels in the margins.” Scientists had therefore begun to assume that if more of the Arctic was uncovered this would help balance the CO2 emitted into the atmosphere by burning fossil fuels. Read the rest of this entry »

Roast crabs, birds and… butterflies?

Many different sea creatures are directly threatened by rising temperatures and also through lower resistance to disease, and lower growth rates. Credit: George Somero

Many different sea creatures are directly threatened by rising temperatures and also through lower resistance to disease, and lower growth rates. Credit: George Somero

Creatures used to warm temperatures could be more threatened by climate change than those from colder environments. That’s according to George Somero, top-billed speaker at the “Global Change and Global Science: Comparative Physiology in a Changing World” conference, held in Colorado last week. Comparative physiology studies how different organisms function and adapt to diverse and changing environments, and according to Somero, gives the scientific community a “crystal ball” for predicting the effects of global warming. Comparing different species to each other, as well as to other members of that species that live in different environments, helps to understand what their ideal conditions and their limits are.

At the conference Somero, who works at Stanford University’s Hopkin’s Marine Station, told how he had looked at porcelain crabs using this approach. Porcelain crabs that live in tropical climates are better able to cope with heat than their relatives from colder parts. While we might expect the tropical crabs to be better equipped to deal with even warmer temperatures, this is not the case. “Tropical porcelain crabs that live at high temperatures, live right near the edge of their thermal tolerance range,” Somero explained. “They have little ability to further increase their thermal tolerance by acclimation.” So, in fact, the tropical crabs have less room to adapt than their temperate counterparts. Read the rest of this entry »

Driving up temperatures

While flying has a greater warming impact in the short term, it's actually less warming than driving in the long term - although the warming impact at all timescales must be considered. Credit: iStock

While flying has a greater warming impact in the short term, it's actually less warming than driving in the long term - although the warming impact at all timescales must be considered. Credit: iStock

Driving alone in a car increases global temperatures in the long run more than making the same long-distance journey by air, Austrian and Norwegian researchers said this week. “Car travel emits more CO2 than air travel per passenger mile,” explained Jens Borken-Kleefeld of Austria’s International Institute for Applied Systems Analysis. As CO2 is a very stable chemical, remaining in the atmosphere longer than other gases, cars have a greater long-term impact on climate change. However, aeroplanes’ impact is greater in the short term. “As planes fly at high altitudes, their impact on ozone and clouds is disproportionately high, though short lived,” Borken-Kleefeld said. Writing in the August issue of Environmental Science and Technology, his team point out that all forms of transport are being used all the time. It’s important, therefore, to tackle air pollutants leading to both short-term and long-term warming.

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Coral and chatting climate: Tougher than they seem

University of British Columbia's Professor Simon Donner

University of British Columbia's Professor Simon Donner

Simon Donner says that in 30 to 50 years, if they do not adapt, we will see corals bleaching and starving dangerously frequently as the oceans warm up. “Corals, the stationary animals that build reefs, get most of their food from colourful algae which live in the coral tissue,” the University of British Columbia professor explained. “When the surrounding waters gets too hot, the corals expel the algae and lose pigmentation. If the heat stress persists, the corals can essentially starve to death.”

Donner points out that the levels of greenhouse gases already in the atmosphere today will create enough warming for this to happen by themselves – a situation he calls “committed warming”. “Even if we froze the greenhouse gas concentrations in the atmosphere today, the climate is going to keep warming for several decades,” he says. However, talking at a conference back in February, he also looked at how corals will adapt to temperature, citing some studies showing that they can increase their temperature tolerances by as much as 1.5°C. Read the rest of this entry »