Thursday, October 20, 2011

Climate change to spark more floods, says UK adviser

Karen Kissane, London 
The Age, October 21, 2011   

AUSTRALIA can expect more frequent devastating floods similar to those in Queensland last year, and the world is facing decades of unprecedented hardship as a result of climate change, according to the chief scientific adviser to the British government.

''We are facing what I believe will be unprecedented difficult times over the next 20, 30, 40 years,'' warned Professor Sir John Beddington. He was speaking as chairman of a panel of scientists launching a major international report about the effects of climate change on people.

The report predicts that migration will increase markedly; that millions will move into, rather than away from, environmentally vulnerable areas; and millions more will be affected but will not be able to move.

The report says that by 2060, up to 179 million people will be trapped in low-lying coastal floodplains subject to extreme weather events such as floods, storm surges, landslides and rising sea levels, unable to migrate because they are too poor or ill-equipped, or because they are restricted by political or geographic boundaries.

Two-thirds of the world's cities with populations of more than 5 million are at least partially located in coastal zones, including rapidly growing urban centres in Asian and African ''mega-deltas'', the report said.
Other large cities would suffer water shortages, with 150 million people already living in cities where water is limited.

Migration and Global Environmental Change is the result of a two-year peer-reviewed project by 350 specialists in 30 countries. Speaking after the launch yesterday, Sir John told The Age that Australia should not expect the La Nina phenomenon that triggered the Queensland floods to be a once-in-a-generation event. The next one could not be predicted but it would return much more frequently than in the past.

''We know that climate change is happening,'' he said. ''We know that the greenhouse gases already in the upper atmosphere will determine the climate over the next 30 years [and there will be] more droughts, floods and extreme weather such as tropical storm surges.''

The World Bank said it will meet in December to assess the report's implications. The International Organisation for Migration said it would organise an international meeting in Geneva to discuss action.

Friday, October 14, 2011

The impact of ecological limits on population growth

Demographers are predicting that world population will climb to 10 billion this century. But with increasing pressure on water and food supplies will this projected population boom turn into a bust?

Robert Engelman for Yale Environment 360, part of the Guardian Environment Network,, Friday 14 October 2011

The hard part about predicting the future, someone once said, is that it hasn't happened yet. So it's a bit curious that so few experts question the received demographic wisdom that the Earth will be home to roughly 9 billion people in 2050 and a stable 10 billion at the century's end. Demographers seem comfortable projecting that life expectancy will keep rising while birth rates drift steadily downward, until human numbers hold steady with 3 billion more people than are alive today.

What's odd about this demographic forecast is how little it seems to square with environmental ones. There's little scientific dispute that the world is heading toward a warmer and harsher climate, less dependable water and energy supplies, less intact ecosystems with fewer species, more acidic oceans, and less naturally productive soils. Are we so smart and inventive that not one of these trends will have any impact on the number of human beings the planet sustains? When you put demographic projections side by side with environmental ones, the former actually mock the latter, suggesting that nothing in store for us will be more than an irritant. Human life will be less pleasant, perhaps, but it will never actually be threatened.

Some analysts, ranging from scientists David Pimentel of Cornell University to financial advisor and philanthropist Jeremy Grantham, dare to underline the possibility of a darker alternative future. Defying the optimistic majority, they suggest that humanity long ago overshot a truly sustainable world population, implying that apocalyptic horsemen old and new could cause widespread death as the environment unravels. Most writers on environment and population are loathe to touch such predictions. But we should be asking, at least, whether such possibilities are real enough to temper the usual demographic confidence about future population projections.

For now, we can indeed be highly confident that world population will top 7 billion by the end of this year. We're close to that number already and currently adding about 216,000 people per day. But the United Nations "medium variant" population projection, the gold standard for expert expectation of the demographic future, takes a long leap of faith: It assumes no demographic influence from the coming environmental changes that could leave us living on what NASA climatologist James Hansen has dubbed "a different planet."
How different? Significantly warmer, according to the 2007 assessment of the Intergovernmental Panel on Climate Change — as much as 10 degrees Fahrenheit more than today on average. Sea levels from two to six feet higher than today's — vertically, meaning that seawater could move hundreds of feet inland over currently inhabited coastal land. Greater extremes of both severe droughts and intense storms. Shifting patterns of infectious disease as new landscapes open for pathogen survival and spread. Disruptions of global ecosystems as rising temperatures and shifting precipitation patterns buffet and scatter animal and plant species. The eventual melting of Himalayan glaciers, upsetting supplies of fresh water on which 1.3 billion South Asians and Chinese (and, of course, that number is rising) depend for food production.

And that's just climate change, based on the more dramatic end of the range the IPCC and other scientific groups project. Yet even if we leave aside the likelihood of a less accommodating climate, population growth itself undermines the basis for its own continuation in other ways. Since 1900, countries home to nearly half the world's people have moved into conditions of chronic water stress or scarcity based on falling per-capita supply of renewable fresh water. Levels of aquifers and even many lakes around the world are falling as a result. In a mere 14 years, based on median population projections, most of North Africa and the Middle East, plus Pakistan, South Africa and large parts of China and India, will be driven by water scarcity to increasing dependence on food imports "even at high levels of irrigation efficiency," according to the International Water Management Institute.

The world's net land under cultivation has scarcely expanded since 1960, with millions of acres of farmland gobbled by urban development while roughly equal amounts of less fertile land come under the plow. The doubling of humanity has cut the amount of cropland per person in half. And much of this essential asset is declining in quality as constant production saps nutrients that are critical to human health, while the soil itself erodes through the double whammy of rough weather and less-than-perfect human care. Fertilizer helps restore fertility (though rarely micronutrients), but at ever-higher prices and through massive inputs of non-renewable resources such as oil, natural gas, and key minerals. Phosphorus in particular is a non-renewable mineral essential to all life, yet it is being depleted and wasted at increasingly rapid rates, leading to fears of imminent "peak phosphorus."

We can recycle phosphorus, potassium, nitrogen, and other essential minerals and nutrients, but the number of people that even the most efficient recycling could support may be much less than today's world population. In 1997, Canadian geographer Vaclav Smil calculated that were it not for the industrial fixation of nitrogen, the world's population would probably not have exceeded 4 billion people — 3 billion fewer than are alive today. It's likely that organic agriculture can feed many more people than it does currently, but the hard accounting of the nutrients in today's 7 billion human bodies, let alone tomorrow's projected 10 billion, challenges the hope that a climate-neutral agriculture system could feed us all.

Food production also requires many services of nature that conventional agronomy tends to ignore in projecting future food supplies, and the dependability of these services appears to be fraying. Roughly one out of every two or three forkfuls of food relies on natural pollination, yet many of the world's most important pollinators are in trouble. Honeybees are succumbing to the tiny varroa mite, while vast numbers of bird species face threats ranging from habitat loss to housecats. Bats and countless other pest-eaters are falling prey to environmental insults scientists don't yet fully understand. And the loss of plant and animal biodiversity generally makes humanity ever-more dependent on a handful of key crop species and chemical inputs that make food production less, rather than more, resilient. One needn't argue that the rising grain prices, food riots, and famine parts of the world have experienced in the past few years are purely an outcome of population growth to worry that at some point further growth will be limited by constrained food supplies.

As population growth sends human beings into ecosystems that were once isolated, new disease vectors encounter the attraction of large packages of protoplasm that walk on two legs and can move anywhere on the planet within hours. In the last half-century, dozens of new infectious diseases have emerged. The most notable, HIV/AIDS, has led to some 25 million excess deaths, a megacity-sized number even in a world population of billions. In Lesotho, the pandemic pushed the death rate from 10 deaths per thousand people per year in the early 1990s to 18 per thousand a decade later. In South Africa the combination of falling fertility and HIV-related deaths has pressed down the population growth rate to 0.5 percent annually, half the rate of the United States. As the world's climate warms, the areas affected by such diseases will likely shift in unpredictable ways, with malarial and dengue-carrying mosquitoes moving into temporal zones while warming waters contribute to cholera outbreaks in areas once immune.

To be fair, the demographers who craft population projections are not actively judging that birth, death, and migration rates are immune to the effects of environmental change and natural resource scarcity. Rather they argue, reasonably enough, that there is no scientifically rigorous way to weigh the likelihood of such demographic impacts. So it makes more sense to simply extend current trend lines in population change — rising life expectancy, falling fertility, higher proportions of people living in urban areas. These trends are then extrapolated into an assumedly surprise-free future. The well-known investor caveat that past performance is no guarantee of future results goes unstated in the conventional demographic forecast.

Is such a surprise-free future likely? That's a subjective question each of us must answer based on our own experience and hunches. Next to no research has assessed the likely impacts of human-caused climate change, ecosystem disruption, or energy and resource scarcity on the two main determinants of demographic change: births and deaths. Migration related to climate change is a more common subject for research, with projections ranging from 50 million to 1 billion people displaced by environmental factors — including climate change — by 2050. The mainstream projections cluster around 200 million, but no one argues that there is a compelling scientific argument for any of these numbers.

The IPCC and other climate-change authorities have noted that extremely hot weather can kill, with the elderly, immune-compromised, low-income, or socially isolated among the most vulnerable. An estimated 35,000 people died during the European heat wave of 2003. The U.S. Centers for Disease Control and Prevention cites research projecting that heat-related deaths could multiply as much as seven-fold by the century's end.

In the past few years, agronomists have lost some of their earlier confidence that food production, even with genetically modified crops, will keep pace with rising global populations in a changing climate. Already, weather-related disasters, from blistering heat waves to flooded farm fields, have contributed to widening gaps between food production and global consumption. The resulting price increases — stoked also by biofuels production encouraged in part to slow climate change — have led to food riots that cost lives and helped topple governments from the Middle East to Haiti.

If this is what we see a decade into the new century, what will unfold in the next 90 years? "What a horrible world it will be if food really becomes short from one year to the next," wheat physiologist Matthew Reynolds told The New York Times in June. "What will that do to society?" What, more specifically, will it do to life expectancy, fertility, and migration? Fundamentally, these questions are unanswerable from the vantage point of the present, and there's a lesson in this. We shouldn't be so confident that the demographers can expertly forecast what the world's population will look like beyond the next few years. A few demographers are willing to acknowledge this themselves.
"Continuing world population growth through mid-century seems nearly certain," University of California, Berkeley, demographer Ronald Lee noted recently in Science. "But nearly all population forecasts... implicitly assume that population growth will occur in a neutral zone without negative economic or environmental feedback. [Whether this occurs] will depend in part on the success of policy measures to reduce the environmental impact of economic and demographic growth."

It's certainly possible that ingenuity, resilience and effective governance will manage the stresses humanity faces in the decades ahead and will keep life expectancy growing in spite of them. Slashing per-capita energy and resource consumption would certainly help. A sustainable population size, it's worth adding, will be easier to maintain if societies also assure women the autonomy and contraceptive means they need to avoid unwanted pregnancies. For anyone paying attention to the science of climate change and the realities of a rapidly changing global environment, however, it seems foolish to treat projections of 10 billion people at the end of this century as respectfully as a prediction of a solar eclipse or the appearance of a well-studied comet. A bit more humility about population's path in an uncertain and dangerous century would be more consistent with the fact that the future, like a comet astronomers have never spotted, has not yet arrived.

Glacier lakes: Growing danger zones in the Himalayas

Fears rise of huge outburst flooding in the Himalayas as glaciers melt due to climate change

Suzanne Goldenberg at Imja Lake,  Nepal,, Monday 10 October 2011

It's strangely calming to watch the Imja glacier lake grow, as chunks of ice part from black cliffs and fall into the grey-green lake below.

But the lake is a high-altitude disaster in the making – one of dozens of new danger zones emerging across the Himalayas because of glacier melt caused by climate change.

If the lake, situated at 5,100m in Nepal's Everest region, breaks through its walls of glacial debris, known as moraine, it could release a deluge of water, mud and rock up to 60 miles away. This would swamp homes and fields with a layer of rubble up to 15m thick, leading to the loss of the land for a generation. But the question is when, rather than if.

Mountain regions from the Andes to the Himalayas are warming faster than the global average under climate change. Ice turns to water;glaciers are slowly reduced to lakes.

When Sir Edmund Hillary made his successful expedition to the top of Everest in 1953, Imja did not exist. But it is now the fastest-growing of some 1,600 glacier lakes in Nepal, stretching down from the glacier for 1.5 miles and spawning three small ponds.

At its centre, the lake is about 600m wide, and according to government studies, up to 96.5m deep in some places. It is growing by 47m a year, nearly three times as fast as other glacier lake in Nepal.

"The expansion of Imja lake is not a casual one," said Pravin Raj Maskey, a hydrologist with Nepal's ministry of irrigation.

The extent of recent changes to Imja has taken glacier experts by surprise, including Teiji Watanabe, a geographer at Hokkaido University in Japan, who has carried out field research at the lake since the 1990s.

Watanabe returned to Imja in September, making the nine-day trek with 30 other scientists and engineers on a US-funded expedition led by theMountain Institute. He said he did not expect such rapid changes to the moraine which is holding back the lake.

"We need action, and hopefully within five years," Watanabe said. "I feel our time is shorter than what I thought before. Ten years might be too late."

Unlike ordinary flash floods, a glacier lake outburst is a continuing catastrophe.

"It's not just the one-time devastating effect," said Sharad Joshi, a glaciologist at Kathmandu's Tribhuvan University, who has worked on Imja. "Each year for the coming years it triggers landslides and reminds villagers that there could be a devastating impact that year, or every year. Some of the Tibetan lakes that have had outburst floods have flooded more than three times."

But mobilising engineering equipment and expertise to a lake 5,100m up and several days' hard walking away from the nearest transport hub is challenging in Nepal, one of the poorest countries in the world. People living in the small village of Dingboche below the lake say scientists and government officials have been talking about the dangers of Imja for years.

Some years ago one of the visiting experts was so convincing about the dangers of an imminent flood that the villagers packed up all their animals and valuables and moved to the next valley. They came back after a week when the disaster did not materialise, but say it's hard to dismiss the idea that there could be a flood one day.

"When I was 21 I went to the lake and it was black and really small," said Angnima Sherpa, who heads a local conservation group in Dingboche. "Two years ago I went there and it was really big. I couldn't believe it could get so big. It was really scary."

But scientists and engineers still cannot agree on whether to rate Imja as the most dangerous glacier lake in the Himalayas, or a more distant threat.

Mobilising international assistance for large-scale engineering projects during a global recession is also difficult. The Mountain Institute's initiative was to call in experts from the Andes, where Peruvians have developed systems for containing glacier floods since a disaster in the 1940s killed nearly 10,000 people.

Cesar Portocarrero, who heads the department of glaciology at Peru's national water agency, has overseen engineering works to drain more than 30 glacier lakes, building tunnels or channels to drain the water and reduce the risk of flooding.

But he conceded it would be an enormous challenge to apply these methods at Imja.

"It's not easy to say 'we are going to siphon the water out of the lake'," Portocarrero said. "Where do you find the people who can work at high altitudes? How do you move in the equipment? What do you do in bad weather? You have to have exhaustive planning." There are also other contenders for immediate action, with some 20,000 glacier lakes across the Himalayas, although many are concentrated in the Everest region. Bhutan alone has nearly 2,700.

Three of those, known as the Lunana complex, are practically touching, increasing the possibility of cascading floods far more devastating than any rupture at Imja.

"If the barrier fails between them we are going to have a massive glacier lake outburst flood," said Sonam Lhamo, a geologist for the Bhutanese government.

The United Nations Development Programme and other agencies have supported a project to drain the lakes but those funds are running out.

John Reynolds, a British engineer and expert on glacier lakes who has worked in Nepal, argues that the international community has focused on Imja because of its proximity to Everest and trekking routes popular with western tourists. He says there are other, more hazardous lakes elsewhere.

The Nepali government ranks Imja among the six most dangerous glacier lakes in the country largely because it is growing so quickly. More than 12 other such lakes are also seen as high risk.

But Reynolds argued: "Just because a lake is getting bigger doesn't necessarily mean that it is getting more hazardous. As the climate is changing, generally speaking more glacial lake systems are forming.

"The question is how to decide which ones are hazardous now and which ones have the propensity to become hazardous in the future."

Imja, though fast-growing, is held in by a relatively wide moraine, which makes it secure in comparison to some others.

Most glacial lake floods begin as high-altitude tsunamis. A large block of ice falling from a glacier at great height sets off a series of giant waves that wash over the moraine.

That's not such a risk for Imja. The glaciers feeding the lake are gradual in slope, which reduces the risk of a large chunk of ice falling from a great height and setting off large waves.

Watanabe concedes the geography of the lake could keep disaster at bay, at least in the next year or two. But, he says, there are signs that an outlet channel at the bottom of the lake may be widening dangerously.

Reynolds said Nepal and the international community need to think of a Himalaya-wide action plan.

"As the climate is changing more glacial lake systems are forming," he said. "The question is how to decide which are hazardous now and which are going to become hazardous in the future."

Sunday, October 9, 2011

Alps could become snow-free by 2050

David Wroe 
The Age, October 10, 2011  

AUSTRALIA'S ski slopes could be completely bare of natural winter snow by 2050 unless concerted action is taken against global warming, according to a government-commissioned report that paints a grim picture of the effects of climate change on alpine areas.

The report, Caring for our Australian Alps Catchments, has found the Alps, which stretch from Victoria through New South Wales to the Australian Capital Territory, face an average temperature rise of between 0.6 and 2.9 degrees by 2050, depending on how much action the international community takes to combat climate change.

''The effects of climate change are predicted to be the single greatest threat to the natural condition values of the Australian Alps catchments,'' the report states.
Rain, snow and other precipitation will decrease up to 24 per cent over the next four decades, accompanied by more bushfires, droughts, severe storms and rapid runoff, causing heavy erosion.

Australia's major mountain range, which peaks with Mount Kosciuszko at 2228 metres, is vulnerable to climate change and faces a dramatic transformation unless serious efforts are made, the study concluded.

''The scenario that is most likely is that there will be less snow both in total and in area, and that we shift more to summer rainfall,'' said study co-author Roger Good, a retired botanist with the NSW government.

''There won't be snow that sits around and slowly melts as there has been in the past. There will be more storm events in summer and therefore faster run-off, which has a lot of potential impacts in terms of soil erosion and damage to vegetation. The worst-case scenario is that there will be no snow at all … only rainfall in both summer and winter.''

The study looked at the 235 Alps catchments, which provide about 29 per cent of the annual water flows into the Murray-Darling Basin. Towns and cities from Wagga Wagga to Mildura and all the way to Adelaide would be affected by global warming damage to the Alps, Mr Good said.

It was the first full health check on the Alpine catchments since 1957. Six out of 10 of the catchments are in ''poor to moderate'' condition. Less than a quarter are getting better.

Snow cover has already declined by more than 30 per cent since 1954. The spring thaw has happened two days earlier per decade.

Loss of vegetation and more severe storms meant that the catchments would hold less water, leading to more rapid run-off, the report states. This would erode soil and reduce water quality as well as causing dams to overflow.

''They would not be able to regulate the flows,'' Mr Good said. ''We would have less water to actually utilise in future, both for human use and for storing for environmental uses.''

Ski fields should continue to get reasonable natural snow cover if the international community sticks to its ambition of keeping global carbon dioxide levels to 450 parts per million (ppm), up from the present 385 ppm, the report states.

But if less action is taken, leading to a concentration of 550 ppm, cover lasting more than 60 days could be reduced by up to 96 per cent by 2050