The crucial role that Antarctica plays in global climate change and its future contribution to sea-level rise was highlighted today by Professor Chris Rapley, Director of British Antarctic Survey (BAS). Speaking at an international convention on climate change in Bonn, Germany* he presented a summary of the latest scientific results from Antarctica.

Professor Rapley said,
“The issue of sea-level rise is of great concern to all of us. The contribution from Antarctica is the greatest uncertainty in the sea level rise debate. The last IPCC (Intergovernmental Panel on Climate Change - 2001) report warned that Antarctica was a ’slumbering giant’. Recent scientific evidence leads us to believe that the giant is waking up. Policy-makers need to know what the consequences will be for society.”

Computer models suggest that the East Antarctic Ice Sheet may thicken as a result of climate change, but observations from satellites and aircraft show that two other areas are thinning. These conflicting effects and the challenge of measuring them make it difficult at present to predict the contribution of Antarctica to sea level rise, there is no doubt that its role will be significant.

In the last 50 years the Antarctic Peninsula has warmed faster than anywhere else on Earth. Predictions made by BAS scientists in 1998 that the warming threatened several ice shelves were realised in 2002 when, in less than a month, 3200 km of Larsen B ice shelf broke up into thousands of small icebergs. Recent research shows that as a result of ice shelf collapse, the glaciers that drained the peninsula have retreated, thinned and accelerated dramatically. BAS researchers have an urgent focus to assess how much these changes are contributing to sea level rise.

Elsewhere, satellite studies have shown that a large part of the West Antarctic Ice Sheet, which may be prone to collapse, has been shown to be thinning. Earlier this year BAS and US National Science Foundation and the University of Texas scientists completed a huge airborne survey of this, the least explored area of the West Antarctic. The scientists flew 100 000 km collecting data that will allow better prediction of the future contribution of West Antarctica to sea level rise.

Original press release: Antarctica � An Awakening Giant? (BAS)

With a review of energy policy around the corner, this report has been published at a critical time. It underlines the importance of wind energy in meeting our climate change and energy security goals. The report concludes that wind, along with other renewable technologies, “offers the only sustainable and secure option for generating electricity over the long term.”

Today’s report bolsters the role of wind power, making clear that the technology is “a critically important part of the overall energy mix”. The wind industry is expanding rapidly and is expected to contribute about 7% of the nation’s electricity needs by 2010 and potentially 15% or more by 2020 as part of the Government�s renewable energy targets and aspirations. BWEA expects that wind development to 2010 will be split roughly equally between on- and offshore projects.

Furthermore, the report highlights an earlier study that concludes that by 2020 wind power is likely to be the cheapest source of power generation in the UK - cheaper than coal, gas and nuclear - even without a carbon credit. The report has also calculated that the additional cost of generating a fifth of our electricity needs from wind would result in only “a very modest increase in cost for consumers”.

The report produces strong evidence that debunks many of the myths about wind power on key issues such as noise and impact on wildlife. Importantly it dismisses claims that intermittency is a major barrier to large scale deployment of wind power. The report confirms that significant amounts of wind capacity can be integrated onto our electricity network without the need for dedicated back-up and without compromising the nation’s security of supply.

Marcus Rand adds:

The Commission’s positive conclusions will come as no surprise to the three quarters of the UK public that believe wind energy is necessary to meet our current and future energy needs.

Original press release: SDC Report Underlines Critical Importance of Wind Power for The UK (BWEA)

Lisbon, Portugal - Ocean Power Delivery (OPD) is pleased to announce today the signing of an order with a Portuguese consortium, led by Enersis, to build the initial phase of the world�s first commercial wave-farm to generate renewable electricity from ocean waves.

The initial phase will consist of three ‘Pelamis’ P-750 machines located 5km off Portugal’s northern coast, near to P’voa de Varzim. The 8m project will have an installed capacity of 2.25MW, and is expected to meet the average electricity demand of more than 1,500 Portuguese households whilst displacing more than 6,000 tonnes per year of carbon dioxide emissions from conventional generating plant. A letter of intent has also been issued to order a further thirty Pelamis machines (20MW) before the end of 2006 subject to satisfactory performance of the initial phase.

The project is being supplied by Ocean Power Delivery - Portugal SA, a wholly owned subsidiary of OPD with full rights to manufacture Pelamis machines in Portugal. Construction of the project will begin immediately. Richard Yemm, Managing Director of OPD, said: “This is a significant milestone for
our company and for wave energy. We see this order as just the first step in developing the Portuguese market, which has the potential to be worth up to a billion Euros over the next 10 years.”

Gonalo Serras Pereira, Chairman of Enersis, commented: “After seventeen years of experience developing, constructing and operating mini hydro schemes, and nine years with wind farms, we believe wave energy will be the new Portuguese endogenous renewable resource. This move in conjunction with other potential partners may win significant industrial economic benefits for Portuguese companies as the market is developed and wave energy gains competitive advantage with other renewables.”

Announcement of this order follows high profile meetings held recently between British and Portuguese officials at the British Embassy in April. These were attended by the UK government’s Chief Scientific Advisor, Sir David King, who highlighted the need for immediate action to tackle the potential impacts of climate change.

Original press release: Order Signed to Build World�s First Wave Farm In Portugal (Renewable Power Association)

Whether witnessed as destructive waves, gently rolling swells or mesmerizing rhythms along the shoreline, the sea’s energy is immense. In fact, experts estimate that just 0.2 percent of it–in the form of waves, tides, salinity and more–could power the entire world. Although the technology is 15-20 years behind that of wind energy, ocean power is a promising, clean energy source that is more predictable, available and energy-dense than wind is.

Led by Annette von Jouanne and Alan Wallace, engineers at Oregon State University (OSU) have found a way to tap into the ocean’s vast potential by developing ways to harness its energy and use it to produce electricity: buoy systems that can generate power just by floating in the ocean’s undulating swells. One such system, located one to two miles offshore, is a permanent magnet linear generator buoy. An electric coil surrounds a magnetic shaft inside the buoy, and while coil is secured directly to the buoy (see illustration), the magnetic shaft is anchored to the sea floor. When waves cause the coil to move up and down relative to the fixed magnetic shaft, voltage is induced and electricity is generated. Each buoy could potentially produce 250 kilowatts of power, and the technology can be scaled up or down to suit a variety of energy needs. A fleet of about 200 such buoys could power the business district of downtown Portland.

OSU’s proximity to the Pacific coast, combined with strategic research facilities in the OSU Motor Systems Resource Facility and the university’s O.H. Hinsdale Wave Research Laboratory, make it a leader in this new technology. The researchers are planning a demonstration facility to test this developing technology in conjunction with the Electric Power Research Institute and others.

Original press release: New Buoys Convert The Ccean’s Energy Into Electricity (NSF)

The mammoth B-15A iceberg appears poised to strike another floating Antarctic ice feature, a month on from a passing blow that broke off the end of the Drygalski ice tongue. As this Envisat image reveals, this time its target is the ice tongue of the Aviator Glacier.

First discovered in 1955, and named to mark the work done by airmen to open up the Antarctic continent, the Aviator Glacier is a major valley glacier descending from the plateau of Victoria Land along the west side of the Mountaineer Range. It enters the sea at Lady Newnes Bay, where it forms a floating ice tongue that extends into the water for about 25 kilometres.

This Envisat Advanced Synthetic Aperture Radar (ASAR) image was acquired on 16 May 2005 in Wide Swath Mode (WSM), providing spatial resolution of 150 metres across a 400-km swath. ASAR can pierce through clouds and local darkness and is capable of differentiating between different types of ice.

The sensor has been following the movements of B-15A since the beginning of the year, gathering the highest frequency weather-independent dataset of this part of the Ross Sea.

Measuring around 115 kilometres in length with an area exceeding 2500 square kilometres, the B-15A iceberg is the world’s largest free-floating object. It is the largest remaining section of the even larger B-15 iceberg that calved from the Ross Ice Shelf in March 2000 before breaking up into smaller sections.

Since then its B-15A section has drifted into McMurdo Sound, where its presence blocked ocean currents and led to a build-up of sea ice that decimated local penguin colonies, deprived of open waters for feeding. During the spring of this year prevailing currents took B-15A slowly past the Drygalski ice tongue. A full-fledged collision failed to take place, but a glancing blow broke the end off Drygalski in mid-April.

The stretch of Victoria Land coast parallel to B-15A’s current position is unusually rich in wildlife, noted for colonies of Adelie penguins as well as Weddell seals and Skuas. If B-15A were to remain in its current position for any prolonged length of time, the danger is that the iceberg could pin sea-ice behind it, blocking the easy access to open water that local animal inhabitants currently enjoy.

Twin-mode Antarctic observations

Envisat’s ASAR instrument monitors Antarctica in two different modes: Global Monitoring Mode (GMM) provides 400-kilometre swath one-kilometre resolution images, enabling rapid mosaicking of the whole of Antarctica to monitor changes in sea ice extent, ice shelves and iceberg movement.

Wide Swath Mode (WSM) possesses the same swath but with 150-metre resolution for a detailed view of areas of particular interest.

ASAR GMM images are routinely provided to a variety of users including the US National Oceanic and Atmospheric Administration (NOAA) National Ice Centre, responsible for tracking icebergs worldwide.

ASAR imagery is also being used operationally to track icebergs in the Arctic by the Northern View and ICEMON consortia, which provide ice monitoring services as part of the Global Monitoring for Environment and Security (GMES) initiative, jointly backed by ESA and the European Union.

This year also sees the launch of CryoSat, a dedicated ice-watching mission designed to precisely map changes in the thickness of polar ice sheets and floating sea ice.

CryoSat, in connection with regular Envisat ASAR GMM mosaics and SAR interferometry - a technique used to combine radar images to measure tiny centimetre-scale shifts between acquisitions - should answer the question of whether the kind of ice-shelf calving that gave rise to B-15 and its descendants are a consequence of ice sheet dynamics or other factors.

Together they will provide insight into whether such iceberg calving occurrences are becoming more common, as well as improving our understanding of the relationship between the Earth’s ice cover and the global climate.

Original press release: New Collision Looks Imminent for B-15A Iceberg (ESA)

Aside from views of cattails and blackbirds, the marshes in the lower Hudson Valley near New York City offer an amazingly detailed history of the area’s climate. Sediment layers from a tidal marsh in the Hudson River Estuary have preserved pollen from plants, seeds, and other materials. These past remnants allowed researchers from Columbia University, New York, N.Y. and NASA to see evidence of a 500 year drought from 800 A.D. to 1300 A.D., the passing of the Little Ice Age and the impacts of European settlers.

Plants provide an indicator of climate because the well-being of a species is controlled by the temperature and moisture of a region, and whether those conditions suit a type of plant. That’s why if you draw latitudinal or horizontal lines around the world you’ll find very similar species growing along those lines, like tropical plants around the equator, or tundra and northern or boreal forest species in a circumference south of the North Pole.

From the pollen record found in sediments in Piermont Marsh of the lower Hudson Valley, a Medieval Warm period was evident from 800 to 1300 A.D. Researchers know this from the striking increases in both charcoal, a sign of dry vegetation and fires, and pollen from pine and hickory trees. Prior to this warming spell, there were more oaks, which prefer a wetter climate.

The study which appeared in a recent issue of the journal Quaternary Research is important for showing how climate in this region has changed due to natural causes prior to human interventions in the area. Dee Pederson, a researcher at Columbia University’s Lamont-Doherty Earth Observatory (LDEO), Palisades, N.Y., and Dorothy Peteet, a researcher at NASA’s Goddard Institute of Space Studies, New York, N. Y., and LDEO, wrote the study.

During this drought period, a core drilled into the marsh bed showed large influxes of inorganic soil particles, a sign of erosion. Plant roots hold soil in place, but with drought and plant deaths, more erosion occurs.

Droughts like this also make the bay saltier, and evidence of this was found by an increase in salty marsh plants, like saltmarsh cordgrass. The changing salinity of the marshes and estuaries could present future water quality issues in the event of a drought. For example, heading north up the Hudson River, the city of Poughkeepsie draws its municipal water directly from the river. Because the salinity of the river changes with drought, causing saltier water to move further north, salinity changes have the potential to affect the water supply of the city.

During the Little Ice Age from the early 1400s to late 1800s, the vegetation changed again to plants that favored cooler and wetter climates. The core records revealed increases in spruce and hemlock that prefer cooler and wetter climates.

Similarly, when Europeans settled the area they cleared the forests for agriculture. The pollen record reflects this with a vast decline in tree pollen and an increase in pollen from weedy plants like ragweed, plantain, sorrel and dock. Inorganic soil particles also went up following European settlement.

Peteet points out that researchers could use these methods to similarly learn about climate in other parts of the world.

The study was funded by the Hudson River Foundation, the LDEO Investment Fund and NASA.

Original press release: Marshes Tell Story of Medieval Drought, Little Ice Age, and European Settlers near New York City (NASA)