Tag Archives: Sea levels

Antarctic warming could accelerate sea level rise

Warming would cause more Antarctic ice to break off and melt Image: PIK/R.Winkelmann
Rising concern: warming would cause more Antarctic ice to break off and melt
Image: PIK (R.Winkelmann)

By Alex Kirby

An international study says warming is affecting not only the Arctic but also the Antarctic – and that could significantly raise global sea levels much faster than previously predicted.

LONDON, 20 August, 2014 − The effect of climate change on the world’s two polar regions looks like a stark contrast: the Arctic is warming faster than most of the rest of the Earth, while most of Antarctica appears to remain reassuringly locked in a frigid embrace.

But an international scientific team says the reality is quite different. The Antarctic is warming too, it says, and the southern ice could become the main cause of global sea level rise during this century − far sooner than previously thought.

The study, led by the Potsdam Institute for Climate Impact Research (PIK) in Germany, found that ice discharge from Antarctica could contribute up to 37 centimetres to global sea levels by 2100.

Computer simulations

The study is the first comprehensive estimate of the full range of Antarctica’s potential contribution to global sea level rise based on physical computer simulations. It combines state-of-the-art climate models and observational data with various ice models.

The results of the study − published in the European Geosciences Union’s journal, Earth System Dynamics − reproduce Antarctica’s recent contribution to sea level rise, as observed by satellites over the last two decades.

“If greenhouse gases continue to rise as before, ice discharge from Antarctica could raise the global ocean by an additional 1 to 37 centimetres this century,” says the study’s lead author, Anders Levermann, PIK professor of dynamics of the climate system.

“Science needs to be clear about the uncertainty,
so that decision-makers can consider the potential implications . . .”

“This is a big range – which is exactly why we call it a risk. Science needs to be clear about the uncertainty, so that decision-makers on the coast and in coastal mega-cities like Shanghai or New York can consider the potential implications in their planning processes.”

The scientists analysed how rising global average temperatures resulted in a warming of the ocean around Antarctica, influencing the melting of the Antarctic ice shelves.

Antarctica currently contributes less than 10% to global sea level rise and is a relatively minor player in comparison with the impact of the oceans’ increasing thermal expansion and the melting of glaciers.

But the major contributors to future long-term sea level rise are expected to be the huge volumes of ice locked up in Greenland and the Antarctic ice sheets. The marine ice sheets in West Antarctica alone could raise sea level by several metres over a period of several centuries.

The study’s computed projections for this century’s sea level contribution are significantly higher than the upper end of the latest projections by the Intergovernmental Panel on Climate Change. These suggest a probable rise by 2100 of around 60cm, although other estimates put the figure almost twice as high.

Even if governments can agree and enforce strict climate policies limiting global warming below the international target level of a maximum 2°C increase, Antarctica’s contribution to global sea level rise is expected still to range from 0 to 23cm this century.

Critical input

A co-author of the study, Robert Bindschadler, from the NASA Goddard Space Flight Center, said: “This paper is a critical input to projections of possible future contributions of diminishing ice sheets to sea level by a rigorous consideration of uncertainty of not only the results of ice sheet models themselves but also the climate and ocean forcing driving the ice sheet models.

“Billions of dollars, euros, yuan, etc, are at stake, and wise and cost-effective decision-makers require this type of useful information from the scientific experts.”

But major modeling challenges still remain. Datasets of Antarctic bedrock topography, for instance, are still inadequate, and some physical processes of interaction between ice and ocean cannot yet be sufficiently simulated.

The team also emphasises that the study’s results are limited to this century, while all 19 of the comprehensive climate models used show that the impacts of atmospheric warming on Antarctic ice shelf cavities will hit with a time delay of several decades.

However, Levermann says: “Earlier research indicated that Antarctica would become important in the long term. But pulling together all the evidence, it seems that Antarctica could become the dominant cause of sea level rise much sooner.” − Climate News Network

Canada puts oil exploitation before forests

A plane drops a water bomb on a forest fire in Ontario, Canada Image: {Per via Wikimedia Commons
A plane drops a water bomb on a forest fire in Ontario, Canada
Image: Per via Wikimedia Commons

By Paul Brown

Having repudiated the Kyoto Protocol on reducing fossil fuel use, Canada is still exploiting tar sands for oil − despite accepting that climate change is destroying its forests.

LONDON, 9 August, 2014 − Detailed evidence that Canada’s vast natural areas are undergoing major changes because of climate change is produced in a new report by Natural Resources Canada.

The government body describes problems with disappearing glaciers, sea level rise, melting permafrost and changing snow and rainfall patterns. One of the country’s most important natural resources, the forests that cover more than 50% of its land area, is under pressure because of pests, fire and drought.

There may, the reports says, be some pluses for Canada in climate change − at least in the short term − because some staple cereal crops will also be able to be grown further north because of warmer weather, assuming that the soil is suitable.

The report, Canada in a Changing Climate, concentrates on impacts and adaptation, but does not mention the causes, or the fact that Canada is now an international pariah in the environmental community because of its exploitation of tar sands for oil.

The country does attempt, for economic reasons, to be more energy efficient, but has repudiated the Kyoto Protocol and international efforts to curb fossil fuel use. The country had accepted a target of cutting emissions on 1990 levels by 5% by 2012, but the government backed out in 2011.

Highest emissions

Average greenhouse gas emissions for oil sands extraction and upgrading are estimated to be 3.2 to 4.5 times as intensive per barrel as for conventional crude oil produced in Canada or the US. If Alberta, where the oil is produced from tar sands, was a country and not a merely a province of Canada, it would have the highest per capita greenhouse gas emissions in the world.

The only mention the report makes of tar sands extraction is the problem caused by its large use of water, and it makes the point that the industry is recycling as much as possible.

A tar sands mine at Mildred Lake, Alberta Image: TastCakes/Janitzky via Wikimedia Commons
A tar sands mine at Mildred Lake, Alberta
Image: TastyCakes/Janitzky via Wikimedia Commons

Mitigation is not on the agenda, as the country’s politicians are intent on exploiting as much of the country’s oil and gas as possible.

A study of forests says that 224,410 people are directly employed in the sector, although it makes up only 1.1% of GDP. About 5% of the forests are damaged annually because of outbreaks of pests and fire. Temperatures in the forest areas have risen far more sharply than on the rest of the planet, with far-reaching consequences for the future, the report says.

In 2009, over three million hectares of forest were destroyed by fire in a single year. The number of fires is expected to increase, with the area being burned being three to five times as much in Western Canada by the end of the century. Large fires are raging again this year, but the quantity of the damage has yet to be assessed.

Severe outbreaks

One of the pests moving north and devastating mature trees is the mountain pine beetle. The beetle is endemic, but is killed by winter temperatures below minus 35˚C, thus limiting its numbers from year to year. However, winter temperatures in many areas now fail to drop below this level, leading to larger and more severe outbreaks of the pest.

A report in 2012 concluded that 18.1 million hectares of forest dominated by mature Lodgepole pine (Pinus contorta) had been affected. Scientists conclude that productivity of the forests will decline rapidly in British Columbia, and thousands of jobs will be lost. Meanwhile, the beetle is continuing to move north and east.

One advantage of the increased temperatures in Canada is that trees can grow further north and higher up mountains than previously, and there is a longer growing season.

Trees that live 100 years cannot migrate fast enough to take advantage, so local governments are going in for assisted migration.

This involves planting the seeds of suitable species 100 to 200 metres above the existing tree line on mountains, and in some cases two degrees of latitude northwards (about 100 miles) of the existing forests into what is currently tundra or scrub. – Climate News Network

Ignoring climate risks could sink US economy

Flood devastation after Hurricane Katrina hit Louisiana in 2005 Image: Infrogmation via Wikimedia Commons
Harsh reminder: devastation after Hurricane Katrina hit Louisiana in 2005
Image: Infrogmation via Wikimedia Commons

By Alex Kirby

Failure to factor immediate action on climate change into American policies and business plans aimed at economic prosperity will lead to havoc, warns former US Treasury Secretary.

LONDON, 3 August, 2014 − For the second time in a month, Americans have been warned that the economic cost of not acting on climate change is likely to be calamitous.

Robert Rubin, the co-chairman of the influential, non-partisan Council on Foreign Relations, says the price of inaction could be the US economy itself.

Writing in the Washington Post, Rubin, a former US Treasury Secretary, argues: “When it comes to the economy, much of the debate about climate change − and reducing the greenhouse gas emissions that are fuelling it − is framed as a trade-off between environmental protection and economic prosperity,

“But from an economic perspective, that’s precisely the wrong way to look at it. The real question should be: ‘What is the cost of inaction?’”

Widespread disruption

He backed the Risky Business Project, a research initiative chaired by a bi-partisan panel and supported by him and several other former Treasury Secretaries. It reported in June that the American economy could face significant and widespread disruption from climate change unless US businesses and policymakers take immediate action.

In his opinion article in the Washington Post, Rubin argues that, in economic terms, taking action on climate change will prove far less expensive than inaction. He wrote: “By 2050, for example, between $48 billion and $68 billion worth of current property in Louisiana and Florida is likely to be at risk of flooding because it will be below sea level. And that’s just a baseline estimate; there are other scenarios that could be catastrophic.

“Then, of course, there is the unpredictable damage from superstorms yet to come. Hurricane Katrina and Hurricane Sandy caused a combined $193 billion in economic losses; the congressional aid packages that followed both storms cost more than $122 billion.

“And dramatically rising temperatures in much of the country will make it far too hot for people to work outside during parts of the day for several months each year − reducing employment and economic output, and causing as many as 65,200 additional heat-related deaths every year.”

Rubin believes a fundamental problem with tackling climate change is that the methods used to gauge economic realities do not take climate change into consideration. He wants climate-change risks reflected accurately, and companies required to be transparent in reporting vulnerabilities tied to climate.

“If companies were required to highlight their exposure to climate-related risks, it would change investor behaviour, which in turn would prod those companies to change their behaviour,” he argues.

Flawed picture

“Good economic decisions require good data. And to get good data, we must account for all relevant variables. But we’re not doing this when it comes to climate change − and that means we’re making decisions based on a flawed picture of future risks.

“While we can’t define future climate-change risks with precision, they should be included in economic policy, fiscal and business decisions, because of their potential magnitude.”

Rubin says the scientific community is “all but unanimous” in agreeing that climate change is a serious threat. He insists that it is a present danger, not something that can be left to future generations to tackle.

“What we already know is frightening, but what we don’t know is more frightening still,” he writes. “For example, we know that melting polar ice sheets will cause sea levels to rise, but we don’t know how negative feedback loops will accelerate the process. . . And the polar ice sheets have already started to melt.”

He concludes: “We do not face a choice between protecting our environment or protecting our economy. We face a choice between protecting our economy by protecting our environment − or allowing environmental havoc to create economic havoc.”

The White House’s Council of Economic Advisers  has estimated that the eventual cost of cutting greenhouse gas emissions will increase by about 40% for every decade of delay, because measures to restrict them will be more stringent and costlier as atmospheric concentrations grow. − Climate News Network

Bold pathways point to a low-carbon future

Brighter future? Sunrise over a wind farm in the Cambridgeshire Fens, UK Image: David Clare/Climate News Network
Brighter future? Sunrise over a wind farm in the Cambridgeshire Fens, UK
Image: David Clare/Climate News Network

By Alex Kirby

The positive message from a scientific report for the UN Climate Summit is that the tough task of cutting CO2 emissions to limit global temperature rise to below 2°C is definitely achievable by following a set of bold, practical steps.

LONDON, 11 July 2014 − Scientists often hesitate to give a cut-and-dried, yes-or-no answer when asked how serious climate change is going to be, and whether the world can still escape significant damage.

Surprisingly, perhaps, a report prepared for a UN conference in September is unequivocal. Yes, it says − the worst is not bound to happen.

The good news is that the world can keep climate change within what are thought to be acceptable limits. The less good news is that while it is possible, it certainly won’t be easy.

The report shows how the countries that emit the most greenhouse gases (GHGs) can cut their carbon emissions by mid-century to prevent dangerous climate change. Prepared by independent researchers in 15 countries, it is the first global co-operation to identify practical pathways to a low-carbon economy by 2050.

The Deep Decarbonisation Pathways Project (DDPP) report is an interim version prepared for the UN Climate Summit to be held in New York on 23 September. The full DDPP report will be ready in the spring of 2015.

Dangerous change

The UN Secretary-General, Ban Ki-Moon, said the report tried to show how countries could help to achieve the globally-agreed target of limiting temperature rise to below 2°C. “Ambitious national action is critical to averting dangerous climate change,” he said. “This report shows what is possible.”

The report aims to help countries to set bold targets in the run-up to the UN climate talks to be held in Paris in 2015.

The work is led by the Sustainable Development Solutions Network (SDSN), an initiative of Columbia University’s Earth Institute for the UN, and the Institute for Sustainable Development and International Relations (IDDRI), a policy research institute based in Paris.

Jeffrey Sachs, the director of the SDSN, said the world had committed itself to limit warming to below 2°C, but not to practical ways of achieving that goal.

He said: “This report is all about the practicalities.  Success will be tough – the needed transformation is enormous – but is feasible, and is needed to keep the world safe for us and for future generations.”

“The issue is to convince the world that the future is as important as the present”

Fatih Birol, chief economist of the International Energy Agency, said: “The issue is to convince the world that the future is as important as the present. Paris 2015 may well be our last hope.”

Despite the global agreement to stay below 2°C, the world is on a path that, without action, will lead to an increase of 4°C or more. The Intergovernmental Panel on Climate Change said in its Fifth Assessment Report, known as AR5, that such a rise might exceed the world’s ability to adapt.

It said that a 4°C rise could endanger harvests and cause drastic sea-level rise, spread of diseases, and the extinction of ecosystems.

Some leading climate scientists − including NASA’s former chief climate scientist, Professor James Hansen, who is now at Columbia University − say that even a 2°C rise would be very dangerous. But many politicians regard it as an essential commitment.

The 15 national pathways examined in the report all show the importance of three factors for achieving radically lower carbon emissions.

The first is greatly increased efficiency and conservation in all energy use.

Renewable sources

The second factor is taking the carbon out of electricity by using renewable sources, “such as wind and solar, as well as nuclear power, and/or the capture and sequestration of carbon emissions from fossil-fuel burning”.

Nuclear energy still attracts widespread and determined opposition, and carbon capture and sequestration (trapping CO2 emissions and storing them underground or beneath the sea floor) has not yet proved that it can work on a commercial scale.

The third factor involves replacing fossil fuels in transport, heating and industrial processes with a mix of low-carbon electricity, sustainable biofuels, and hydrogen.

The authors say their interim report shows the critical long-term importance of preparing national deep decarbonisation plans for 2050.

Emmanuel Guerin, the DDPP’s senior project manager, said the pathways were crucial to shaping the expectations of countries, businesses and investors. − Climate News Network

Climate puts US at risk of multi-billion bill

Overheating: US crops such as cotton face a %20 drop in yield Image: Wars via Wikinmedia Commons
Overheated economy: US crops such as cotton face a 20% drop in yield
Image: Wars via Wikimedia Commons

By Alex Kirby

A study of the possible cost of climate change to the US economy warns government and business that billions of dollars could be at risk through damage to property, reduced harvests and workers incapacitated by extreme heat.

LONDON, 29 June, 2014 − The sheer economic cost of climate change to Americans could be far greater than many realise, an influential study says.

The study was commissioned by the Risky Business Project, a research organisation chaired by a bi-partisan panel and supported by several former US Treasury Secretaries.

It expects climate change to have varied impacts across different regions and industries. Rising sea levels, it says, could destroy many billion dollars’ worth of coastal properties by 2050, and warming temperatures, especially in the south, south-west and mid-west, could cut the productivity of people working outdoors by 3%.

Without a change in crops, harvests in these regions could fall by 14%. But further north, in states such as North Dakota and Montana, winter temperatures will probably rise, reducing frost and cold-related deaths and lengthening the growing season for some crops.

Kate Gordon, executive director of the Risky Business Project, said : “We still live in a single integrated national economy, so just because it’s not hot where you are doesn’t mean you won’t feel the heat of climate change.”

Michael Bloomberg, a former mayor of New York, said: “Damages from storms, flooding, and heat waves are already costing local economies billions of dollars. We saw that firsthand in New York City with Hurricane Sandy.

Costs of inaction

“With the oceans rising and the climate changing, the Risky Business report details the costs of inaction in ways that are easy to understand in dollars and cents − and impossible to ignore.”

Hank Paulson, a former Treasury Secretary and co-chair of the Risky Business Project, said the report shows us that “our economy is vulnerable to an overwhelming number of risks from climate change.

“But if we act immediately, we can still avoid most of the worst impacts of climate change and significantly reduce the odds of catastrophic outcomes. But the investments we’re making today will determine our economic future.”

In a section on short-term climate threats, the authors say: “The American economy is already beginning to feel the effects of climate change. These impacts will likely grow materially over the next 5 to 25 years…”

“Just because it’s not hot where you are doesn’t mean
you won’t feel the heat of climate change”

They say there is a 1-in-20 chance of yield losses of more than 20% in corn, wheat, soya and cotton crops over that timespan.

On energy, they say changes in temperature driven by greenhouse gases will probably mean a need to build roughly 200 average coal-fired or natural gas-fired power plants between 2020 and 2045, costing up to $12 billion per year.

Climate impacts, the report says, are unusual because future risks are directly tied to present decisions. By failing to lower greenhouse gas emissions today, decision-makers put in place processes that increase overall risks tomorrow.

By 2050, on present trends, $66bn-$106bn worth of existing coastal property will probably be below sea level nationwide, with $238-$507bn worth by 2100.

By mid-century, the average American will probably see 27 to 50 days over 95°F (35°C) each year − two to more than three times the average annual number of such days seen over the last 30 years. By the end of the century, this number will probably average 45 to 96 days over 95°F each year.

But the study says that the south-west, south-east, and upper mid-west will probably see several months of 95°F days annually.

Human threshold

In the longer term, extreme heat during parts of the year could pass the threshold at which the human body can no longer maintain a normal core temperature without air conditioning. At these times, anyone who has to work outdoors, or without access to air conditioning, will face severe health risks and possible death.

The authors say they hope it will become standard practice for the American business and investment community to factor climate change into its decision-making process. They say: “We are already seeing this response from the agricultural and national security sectors; we are starting to see it from the bond markets and utilities as well.

“But business still tends to respond only to the extent that these risks intersect with core short-term financial and planning decisions.”

And the authors warn the government: “We also know that the private sector does not operate in a vacuum, and that the economy runs most smoothly when government sets a consistent policy and a regulatory framework within which business has the freedom to operate.

“Right now, cities and businesses are scrambling to adapt to a changing climate without sufficient federal government support…” − Climate News Network

Underworld threat to melting icecap

 

Concealed beneath the Petermann glacier are towering blocks of ice Image: Michael Studinger/NASA via Wikimedia Commons
Concealed beneath the Petermann glacier are towering blocks of ice
Image: Michael Studinger/NASA via Wikimedia Commons

By Tim Radford

Radar images of Greenland’s glaciers have revealed a spectacular underground landscape of “skyscraper” ice blocks created by a melt-and-freeze cycle that is accelerating the reduction of the icecap

LONDON, 16 June − Researchers in the US have identified a new reason for the acceleration in the melting of Greenland’s icecap − the ice underneath, as it melts and then refreezes, appears to speed up glacial flow.

The melt-and-freeze-again cycle is not itself new, as a similar process has been diagnosed under the ice cap of Antarctica. Nor is the process itself necessarily connected with global warming. Such things must always have happened.

But Robin Bell, a geophysicist at Columbia University’s Lamont Doherty Earth Observatory, reports with colleagues in Nature Geoscience that they used ice-penetrating radar to identify ragged blocks of ice as tall as skyscrapers and as wide as the island of Manhattan at the very bottom of the ice sheet. These structures cover about a tenth of the island and seem to form as melted water below the ice freezes again. They then warp the ice around and above them.

Easier to flow

“We see more of these features where the ice sheet starts to go fast,” Professor Bell said. “We think the refreezing process uplifts, distorts and warms the ice above, making it softer and easier to flow.”

Bell and her colleagues looked at the Petermann Glacier in Greenland’s north, which in 2010 pushed a huge chunk of ice into the sea. Observations suggest that the glacier is moving twice as fast as the surrounding ice, and the hypothesis is that the melt-and-freeze-again process is contributing to this acceleration.

Researchers have been troubled for a decade or more by the apparent increase in ice loss from Greenland. Were the whole island to melt, sea levels worldwide would rise by more than seven metres, so the concern is practical.

Recently, researchers have found that the bedrock beneath many glaciers is actually below sea level, making the glaciers vulnerable from ocean inflow. They have identified a process called “dynamic thinning”, triggered by warmer air temperatures, and they know anyway that natural geothermal heat flow mis likely to melt the base of the ice and lubricate any acceleration.

They have measured a fourfold increase since 1997 in summer flow speeds in the island’s Jakobshavn glacier. And they have indicated that the Greenland icecap each summer becomes more vulnerable to melting because the snows themselves are becoming darker, as more dust blows in from areas that are increasingly ice free.

Ice slide

So the discovery of a process that will make the ice slide to the sea more efficiently is not of itself more sinister. The meltwater could come from a number of sources. The friction created by a glacier as it moves must contribute. So could natural heat flow from the bedrock. Surface ice could melt in the summer sun and drain through crevasses to the base.

However, what the discovery helps to offer, literally and metaphorically, is a deeper understanding of the processes at work below the ice.

What is not clear is whether the melt-and-freeze cycle will influence the rate at which ice is lost in future. Nor does anyone yet know what triggers the cycle.

“The conditions under which such switches occur should be investigated, as they directly affect the ability of an ice sheet to slide over its bed,” advises Joseph A. McGregor, of the University of Texas at Austin, writing in the same issue of Nature Geoscience. − Climate News Network

Dark shadow falls on melting icecap

 

Signs of melting as darkness falls on the Greenland icecap Image: Matthew Hoffmann/NASA ICE via Wikimedia Commons
Signs of melting can be seen as darkness descends on the Greenland icecap
Image: Matthew Hoffmann/NASA ICE via Wikimedia Commons

By Tim Radford

Dust blowing in from warming areas of the Arctic is causing the Greenland icecap to melt faster by reducing the whiteness that reflects light and keeps it cool 

LONDON, 13 June − French scientists have identified a new mechanism that could cause the Greenland icecap to melt even faster – because dust is making its surface darker.

Marie Dumont, of the French national meteorological service, Météo-France, reports with colleagues in Nature Geoscience that, since 2009, the snows of the Arctic region’s biggest single permanent white space have been steadily darkened by “light-absorbing impurities” − known to the rest of the world simply as dust.

The Arctic has always been cold and white, simply because it is not just cold but is also white. The phenomenon is called albedo. Regions with a high albedo reflect light and stay cooler, so ice is a form of self-insulation.

Conversely, things that absorb light become warmer − and satellite data analysed by Dr Dumont and her fellow researchers shows that the Greenland ice is getting darker in the springtime.

They think the dust is blowing in from areas of the Arctic that are losing snow cover much earlier in the season as the climate warms. And, they calculate, this steady darkening alone has led to “significant” melting of the icecap.

This finding is ominous. What the researchers have identified is yet another case of what engineers call positive feedback. In the last 30 years, the Arctic sea ice has been in retreat, and researchers expect that, later in the century, the Arctic ocean will be entirely free of ice most summers.

Insulating layers

That means that there will be more atmospheric dust each spring, landing on the snows of Greenland and lowering its albedo even more, so the insulating layers of ice on the huge island will continue to retreat.

Researchers have twice in the last few months had to revise their predictions for the melting of the Greenland glaciers. The continued melting of the ice sheet is expected to raise global sea levels by 20cm by 2100, and since the whole ice sheet – which would take much longer to melt − holds enough frozen water to raise sea levels by more than seven metres, what happens in Greenland matters very much to maritime cities as far apart as Miami and Mumbai.

The French researchers have backed up their observations with a computer model of potential surface melt in Greenland. If a perfect reflecting surface would have a value of one, then meteorologists allot a value of 0.9 to the albedo of fresh snow. They calculate that a decrease in the albedo of even a very small ratio, such as 0.01, could lead to the melting of 27 billion tons of ice every year.

They are not saying that this is already happening, but they do argue that “future trends in light-absorbing impurities should therefore be considered in projections of Greenland’s mass loss”.

Accelerating warming

This is not the only newly-identified potential mechanism for positive feedback. A report by Laetitia Pichevin, of the University of Edinburgh’s School of GeoSciences, Scotland, and fellow researchers, was published in the same issue of Nature Geoscience. It says that rising global temperatures could decrease the amount of carbon dioxide naturally taken up by the world’s oceans, thus also accelerating global warming. This, too, is another process that could go on accelerating.

The researchers analysed sediments laid down 26,000 years ago in the Gulf of California and measured the abundance of silicon and iron in tiny marine fossils. They found that those periods when silicon was least abundant in ocean waters coincide with relatively warmer climates, low levels of atmospheric iron, and reduced carbon dioxide uptake by the plankton in the oceans.

“We were surprised by the many ways in which iron affects the CO2 given off by the oceans,” Dr Pichevin said. “If warming climates lower iron levels at the sea surface, as occurred in the past, this is bad news for the environment.” – Climate News Network

Help needed now for climate refugees

 

Somalis displaced by drought in 2011 queue to register at a refugee camp in Ethiopia Image: Cate Turton/DFID via Wikimedia Commons
Somalis displaced by drought in 2011 queue at a refugee camp in Ethiopia
Image: Cate Turton/DFID via Wikimedia Commons

By Paul Brown

Governments worldwide are warned of the need to draw up plans urgently to avoid conflict and insecurity by helping populations who are being forced to move because of climate change

 

LONDON, 11 June − Hundreds of thousands of people are already migrating because of climate change, and countries urgently need adaption plans to resettle populations and avoid conflict.

Sea level rise, violent storms and more gradual disasters such as droughts will cause more unplanned mass population movements − either temporary or permanent − and governments need to manage this by planning in advance to protect vulnerable people, says a new report.

The report, by the United Nations University’s Institute for Environment and Human Security, warns that unplanned movements will lead to conflict and insecurity. Governments need to act regionally to anticipate and facilitate the movement of people.

Ideally, for the displaced families, this would mean providing access to land and housing. They would need financial services, health, education, water and sanitation. They would also need jobs and the ability to cover the costs of living and food security.

Move to survive

Economic and environmental factors sometimes combine to cause migration, with people anticipating that they may have to move to survive. This can lead to people moving individually to seek a new life − like many of those currently crossing the Mediterranean to Europe from North Africa − or to whole family groups looking for new lands.

Some countries already faced with voluntary or forced migration because of climate change are involved in relocating populations and are working internationally to find new homes in other countries for their people. This planning allows displaced people to live and work abroad with dignity, rather than be refugees.

An example is Kiribati in the Pacific, where displaced islanders have been trained for new jobs – for example, nursing − in countries such as Australia. Other new jobs include seafaring, teaching and policing. This enables family members to work abroad and support those relatives still at home who want to remain in their islands for as long as possible.

The report studied the national adaption programmes of 50 countries affected by climate change, and which fear that populations will have to move because of climate change. They include low-lying countries such as Bangladesh, a number of Pacific and Caribbean island nations, and dry African countries. The adaptation programmes are available from the UN Framework Convention on Climate Change.

The Nansen Initiative, launched in 2012 by the governments of Norway and Switzerland, is a project designed to study how to help people who are displaced across international borders by the effects of climate change.

The Initiative is in the process of looking at regions particularly affected by climate change that already have problems with migration. These are the Pacific, Central America, the “Greater Horn of Africa”, and South-East Asia and South Asia. The report concludes that all of the Pacific region island countries are already affected by slow and sudden-onset natural hazards, including cyclones, floods and drought.

Dry Corridor

A recent meeting held in Costa Rica heard that, as well as sudden natural disasters, changes in the rainfall pattern have led to what is known as the “Dry Corridor”. Participants discussed the plight of the indigenous people of Kuna, in Panama, where 65,000 individuals were relocated from their low-lying islands to higher ground.

In the Greater Horn of Africa region, climate change is expected to increase the already significant migration of populations caused by droughts and floods. Hundreds of thousands of people were displaced within Somalia or across the borders to Kenya, Ethiopia and Djibouti during the 2010-2011 droughts.

The report concludes that in addition to finding land, homes and jobs for the newcomers so they can support their families, they need to be made part of the community. Planned relocation efforts should be aimed at integration of the newcomers into existing political structures and giving them some participation in decision making about their own futures. The plight of the old and vulnerable, children and women must be considered.

The need is to avoid conflict within families, with authorities and host communities. Efforts should be made to avoid loss of cultural and spiritual identity and traditional knowledge. This will avoid the need for further migration and displacements.− Climate News Network

No way back for West Antarctic glaciers

FOR IMMEDIATE RELEASE

 

Birth of an iceberg: a massive crack appears in the Pine Island glacier in West Antarctica Image: Nasa Earth Observatory via Wikimedia Commons

Birth of an iceberg: a massive crack in West Antarctica’s Pine Island glacier
Image: Nasa Earth Observatory via Wikimedia Commons

By Tim Radford

Satellite data analysis reveals the ominous news that the melting glaciers of West Antarctica have passed the ‘point of no return’ as the southern hemisphere gets warmer

LONDON, 22 May – The glaciers of the West Antarctic may be in irreversible retreat, according to the evidence of satellite data analysed by scientists at the US space agency Nasa.

The study of 19 years of data, due to be reported in the journal Geophysical Research Letters, confirms the ominous news that the southern hemisphere is not just warming − it is that it is warming in a way that speeds up the melting of the West Antarctic glaciers.

Long ago, glaciologists began to wonder whether the West Antarctic ice sheet was inherently unstable. The water locked in the ice sheet in the Amundsen Sea region – the area the Nasa researchers examined − is enough to raise global sea levels by more than a metre. If the whole West Antarctic ice sheet turned to water, sea levels would rise by at least five metres.

Steady change

What the latest research has revealed is a steady change in the glacial grounding line, which is the point in a glacier’s progress towards the sea where its bottom no longer scrapes on rock but starts to float on water. It is in the nature of a glacier to flow towards the sea, and at intervals to calve an iceberg that will then float away and melt. The puzzle for scientists has been to work out whether this process has begun to accelerate.

Eric Rignot, a glaciologist at the Nasa Jet Propulsion Laboratory and the University of California, Irvine, thinks it has. He and his research partners believe that European Space Agency satellite data has recorded the points at which the grounding lines can be identified in a series of West Antarctic glaciers monitored between 1992 and 2011, as the glaciers flexed in response to the movement of tides.

All the grounding lines had retreated upstream, away from the sea − some by more than 30 kilometres. The grounding lines are all buried under hundreds of metres of ice, and are difficult to identify.

The shift of ice in response to tidal ebb and flow provides an important clue. It also signals an acceleration of melting, because it is the glacier’s slowness that keeps the sea levels static. As it inches towards the sea, there is time for more snow and ice to pile up behind it.

Speeds up

But if the water gets under the ice sheet, it reduces friction and accelerates the passage of frozen water downstream. So the whole glacier speeds up, and the grounding line moves yet further upstream.

Something similar has been reported from the glaciers of Greenland. And once the process starts, there is no obvious reason why it would stop. The melting will still be slow, but the latest evidence indicates that it seems to be inexorable.

“We’ve passed the point of no return,” Prof Rignot says. “At current melt rates, these glaciers will be history within a few hundred years.

“The collapse of this sector of West Antarctica appears to be unstoppable. The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable.” – Climate News Network

Reefs merit protection money

FOR IMMEDIATE RELEASE

 

Waves crash ashore on the Southern Pacific island of Niue Image: Gadfium via Wikimedia Commons

Waves sweep in across coral reefs surrounding the Southern Pacific island of Niue
Image: Gadfium via Wikimedia Commons

By Tim Radford

The great natural protective barriers that coral reefs provide for millions of people in coastal communities are seriously threatened, but scientists calculate that restoration projects would cost 20 times less than building artificial breakwaters to keep pounding waves at bay

LONDON, 19 May − Coral reefs, under threat around the tropics from the double menace of global warming and ocean acidification, are also natural protection systems for million people. And the importance of that protection is shown in a new scientific study confirming that a coral reef can reduce the energy of a pounding wave by up to 97%.

It is widely known that reef systems offer a natural barrier. But Filippo Ferrario, from the University of Bologna in Italy, and an international team of researchers report in Nature Communications that they decided to try to put a figure on the effectiveness of a living limestone rampart maintained by a tiny animal that is the basis for a rich submarine ecosystem.

They found that the shallowest part of a reef – the crest where the waves break first – dissipates 86% of the wave’s energy, while the whole reef can reduce the sea’s impact by 97%.

And the cost of maintaining a reef − that is, the cost of a reef restoration project − is US$1,290 per metre, compared with an average $19,791 per metre to build an artificial breakwater. That’s almost 20 times cheaper.

First line of defence

“Coral reefs serve as an effective first line of defence to incoming waves, storms and rising seas,” says study co-author Michael Beck, lead marine scientist of the US Nature Conservancy. “Two hundred million people across more than 80 nations are at risk if coral reefs are not protected and restored.”

Dr Ferrario adds “The study illustrates that the restoration of coral reefs is an important and cost-effective solution to reduce risks from coastal hazards and climate change.”

Marine scientists have argued for decades that natural systems such as mangrove forests, sandspits, water meadows and reefs offer protection for coastal cities. A huge proportion of humanity now lives in cities, and many cities have grown up on estuaries, around natural harbours, or on beach fronts − that is, at or near sea level.

Extreme weather

Sea levels will rise inexorably with global warming, and climate change threatens to increase the frequency and the magnitude of extreme weather events. There have been warnings that, by the end of the century, coastal flooding could cost up to a trillion dollars a year.

But the natural reefs that have offered shelter for so many people – for example, an estimated 41 million in Indonesia, 36 million in India, and 23 million in the Philippines – are under stress from pollution and overfishing.

Corals are also sensitive to rising water temperatures. And, although there is some evidence that some corals can adapt, there are serious concerns about the consequences of change in water chemistry as more and more atmospheric carbon dioxide dissolves in the oceans. – Climate News Network