Tag: Amazon

Adventures in the Anthropocene

Science journalist Gaia Vince left her desk at Nature and spent two years visiting places around the world, some of them very isolated, where people were grappling with the conditions of what is sometimes described as a new epoch, the Anthropocene. It dates from the industrial revolution and represents a different world from the relatively settled Holocene in which human civilisation was able to develop. Adventures in the Anthropocene tells the story of Vince’s encounters with some remarkable individuals and their communities. It also includes lengthy musings on the technologies the future may employ as humanity faces the challenges of climate change, ocean acidification, population growth, resource depletion and more.

Vince goes to the front lines of the human battles. In a remote village in Nepal she describes the extraordinary work of Mahabir Pun who gained a university scholarship in the US and returned years later to bring computers and Wi-Fi to the children of his village. It’s a fascinating story, full of hope for development in his region. But it’s also precarious. Electricity for the computers comes from a small hydro-scheme fed by glacier water. In the same chapter Vince points out that the warming rate in that Himalayan region is five times greater than the global average and the glaciers are melting. Once they are gone there is no meltwater and no power. Levels have already been diminishing in the once-deep stream near the village.

Continue reading “Adventures in the Anthropocene”

Russian roulette with a rainforest

I reported in a November post that it appeared likely that the 2010 Amazon drought was even more severe than the 2005 drought, itself identified as a 1-in-100-year event. Now Simon Lewis of Leeds University and Paulo Brando of Brazil’s Amazon Environmental Research Institute (IPAM) and others have published a paper in Science with rainfall analysis showing that the 2010 drought was indeed more widespread and severe than that of 2005.

The 2005 drought killed billions of trees within the rainforest. On the ground monitoring showed that these forests stopped absorbing CO2 from the atmosphere, and as the dead trees rotted they released CO2 to the atmosphere.

 

The press release reports that this new research, co-led by Dr Lewis and Brazilian scientist Dr Paulo Brando, used the known relationship between drought intensity in 2005 and tree deaths to estimate the impact of the 2010 drought.

They predict that Amazon forests will not absorb their usual 1.5 billion tonnes of CO2 from the atmosphere in both 2010 and 2011, and that a further 5 billion tonnes of CO2 will be released to the atmosphere over the coming years once the trees that are killed by the new drought rot. For context, the United States emitted 5.4 billion tonnes of CO2 from fossil fuel use in 2009.

They can’t be sure, of course, until they have completed forest measurements on the ground and they describe their results as an initial estimate, one which incidentally does not include any emissions from fires which can be extensive during hot and dry years.

The danger is that this could be a precursor of the Amazon rainforest no longer playing the part it does in regulating atmospheric CO2. Simon Lewis:

“Two unusual and extreme droughts occurring within a decade may largely offset the carbon absorbed by intact Amazon forests during that time. If events like this happen more often, the Amazon rainforest would reach a point where it shifts from being a valuable carbon sink slowing climate change, to a major source of greenhouse gasses that could speed it up.”

Of course it is possible that the two droughts are just an unusual natural variation, but Lewis points out that they are consistent with climate models which project a grim future for Amazonia.

Tropical ecologist Daniel Nepstad  is Director of International Programs at IPAM and one of the paper’s authors. He was  interviewed a couple of months ago during the Cancún conference.

“It’s about as bad as we’ve seen. I’ve been working in the Amazon for about 25 years now, and I haven’t seen anything like it. We thought we had the worst drought of the century in 2005, and this one is worse.”

The interviewer comments that the drought in 2005 was called a once-in-a-century drought, just five years ago.

“I know. And, there was a drought in 2007 that didn’t even capture any immediate attention, it wasn’t even worth it because drought is really becoming part of the fabric of the Amazon.”

The cause?

“You know, statistically, it’s just very hard to take an individual event like this mega-drought of the Amazon, and say that it is a direct cause of climate change. But, with both this and the 2005 and the 2007 drought, they’re all consistent with the scenario of increasing accumulation of greenhouse gasses in the atmosphere.”

How does the drought affect the rainforest?

“The forest actually makes the rain in the Amazon. By the end of the dry season, a lot of Amazon trees are sucking water from the soil- it could be 60 feet beneath the ground surface. So, they’re going way down deep to get that water, so that they can keep their green lush canopy, even though they’ve been deprived of water for a few months. And, that water going into the atmosphere makes the clouds that make the rain. Similarly, the rain coming down, if it weren’t for that rain, if those dry seasons got longer on a permanent basis, then that forest would cease to be. It would be replaced by grassy vegetations, savannahs, woodlands and scrub that would burn periodically, and that would look very different and have far fewer species.”

What are scientists supposed to think when confronted with possibilities such as those represented by recent Amazon droughts? That it will be interesting to see whether this is the start of a trend which would confirm predictions of the impacts of increasing greenhouse gases? That without further evidence they must be careful not to sound alarmist? In fact Simon Lewis and Daniel Nepstad are properly cautious, acknowledging that as scientists they can’t say with certainty that these droughts are part of human-caused climate change. But they are also very aware of the magnitude of the danger represented by the droughts if they are the result of increased greenhouse gas emissions. A statement by Lewis reported in a Guardian article expresses succinctly why we can’t just wait to see whether further evidence accumulates.

“We can’t just wait and see because there is no going back. We won’t know we have passed the point where the Amazon turns from a sink to a source until afterwards, when it will be too late.”

In other words the possible consequences are so dire that it is reckless to risk them.

“If greenhouse gas emissions contribute to Amazon droughts that in turn cause forests to release carbon, this feedback loop would be extremely concerning. Put more starkly, current emissions pathways risk playing Russian roulette with the world’s largest rainforest.”

That’s a serious warning from a scientist. And the Amazon is not an isolated case.  Ove Hoegh-Guldberg, in the presentation Gareth has recently posted, is convinced with good reason that ocean ecosystems are already being seriously impacted under current elevated levels of atmospheric CO2 and that a 450 ppm level will be disastrous for ocean life and consequently for us. The world’s ice is clearly under assault from warming, with the likelihood of sea level rise of fearful consequence to human populations, as scientists like James Hansen now regularly warn. The list is long.

We’re playing Russian roulette with more than the rainforests, and the revolver has more than one chamber loaded. The longer we take to start reducing emissions the more we shorten the odds

The Climate Show #3: Cancun and cooling

Climate talks heat up in Mexico, snow blankets Britain and much of Europe, and The Climate Show is at the heart of the action. Glenn and Gareth set the scene for COP16 in Cancun and then interview Oxfam NZ’s Barry Coates at the conference to find out how things are shaping up. Gareth explores the link between Arctic climate change and cold winter weather in Western Europe, John Cook debunks that favourite sceptic myth — that the world’s cooling — and we look at the potential for nuclear power to provide part of the solution to decarbonising the power economy.

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Show notes below the fold.

Continue reading “The Climate Show #3: Cancun and cooling”

I wish it would rain

We (or at least some of us) rightly feel apprehension and alarm at the prospect of melting glacial and polar ice. There are new reminders that we should be equally alarmed at the prospect of Amazonian drought. Joe Romm has written a lengthy post on Climate Progress drawing attention to the 2010 drought which may prove more widespread and severe than the 2005 drought, itself identified as a 1-in-100-year type event.  He quotes an email to that effect from forest scientist and Amazon expert Simon Lewis (he of the Sunday Times fightback and subsequently granted apology).

Lewis recommends an article in the Global Post which is well worth reading.  It refers to three scientists. Oliver Phillips, a tropical ecology professor at the University of Leeds, speaks of his concern that parts of the Amazon may be approaching a threshold point beyond which the eco-system can’t go. He led a team of researchers who studied the damage caused by the 2005 drought which caused a massive die-off of trees and led to the forest expelling carbon dioxide rather than absorbing it. He’s worried that another severe drought is following so soon after the last one.  Greg Asner, an ecologist at the Carnegie Institution for Science, points out that some tropical forests in the world now are starting to be exposed to temperatures they’ve never experienced. His studies show that higher temperatures and shifts in rainfall could leave as much as 37 percent of the Amazon so radically altered that the plants and animals living there now would be forced to adapt, move or die. Foster Brown, an environmental scientist at the federal university in the Brazilian state of Acre, comments that drought has made ecosystems so dry that instead of a being a barrier to fire, the forest became kindling.

Nikolas Kozloff’s book No Rain in the Amazon which I reviewed earlier this year refers to much-cited scientist Philip Fearnside of Brazil’s National Institute for Research in the Amazon, who for some years has observed the connection between drought and El Niño-like conditions which are expected to become more frequent with continued global warming. He too is concerned that the Amazon might dry out and be placed in jeopardy as a result of climate change. Kozloff also reports the belief of some researchers that warming sea surface temperatures in the tropical North Atlantic Ocean are linked to Amazon drought.

In an October press release Brazil’s Amazon Environmental Research Institute (IPAM) comments:

“The drought of 2010 still hasn’t ended in the Amazon and could surpass that of 2005 as the region’s worst during the past four decades… Even if this doesn’t occur, the forest will have already experienced three extreme dry spells in just 12 years, two of which occurred during the past five years: 1998, 2005 and 2010. And this is not including the drought of 2007, which affected only the Southeastern Amazon and left 10 thousand sq. km. of forest scorched in the region…`The Amazon that had wet seasons so well-defined that you could set your calendar to them – that Amazon is gone,’ says ecologist Daniel Nepstad of IPAM…”

Deforestation of the Amazon by humans has long been a major international concern, and Simon Lewis’s communication with Jo Romm indicates that there is a degree of good news on that front in that since 2005 deforestation rates have been radically reduced. But the droughts are bad news. They kill trees and promote damaging fires, “potentially leading to a drought-fire-carbon emissions feedback and widespread forest collapse”. Lewis expresses particular concern that while two unusual droughts clearly don’t make a trend, they are consistent with some model projections made well before 2005: “that higher sea surface temperatures increase drought frequency and intensity, leading later this century to substantial Amazon forest die-back.”

Hot Topic commenter Tony on a previous post linked to an Al Jazeera video clip (which I’ve posted below), with the observation that if anything should motivate a sense of urgency in Cancun, what it portrayed should. Simon Lewis also linked what may be happening in the Amazon to the Cancun conference. Not with any great expectation, but with a dry reminder that the risks to which we are exposing humanity don’t diminish because we ignore them. “While little is expected of the climate change talks in Cancun next week, the stakes, in terms of the fate of the Amazon are much higher than they were a year ago in Copenhagen.”

I hope it doesn’t appear as incidental if I note before concluding that the droughts affect not only the forest and through it the welfare of the whole planet but also the local populations whose livelihood and wellbeing is jeopardised. The Global Post article reports the anxiety of village chief Mariazinha Yawanawa. Her people are sustained by the forest. They hunt in the woods, fish the rivers and grow crops in the clearings where they live.  “Everything has changed. We don’t know when we can plant. We plant and then the sun kills everything. If it continues like this, we expect a tragedy

[The Temptations]

Sceptics face yawning credibility gap

We know that the vast majority of climate scientists support the explanation of anthropogenic climate change set out by the Intergovernmental Panel of Climate Change. That majority is now quantified in the first study of its kind published yesterday in the Proceedings of the National Academy of Sciences, Expert credibility in climate change.

“Here, we use an extensive dataset of 1,372 climate researchers and their publication and citation data to show that (i) 97–98% of the climate researchers most actively publishing in the field support the tenets of anthropogenic climate change (ACC) outlined by the Intergovernmental Panel on Climate Change, and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of anthropogenic climate change are substantially below that of the convinced researchers.”

The study explains the criteria by which these conclusions were reached, paying particular attention to the question of expertise, where weight was given to the number of climate publications of researchers and to their citation levels.

“We show that the expertise and prominence, two integral components of overall expert credibility, of climate researchers convinced by the evidence of ACC vastly overshadows that of the climate change skeptics and contrarians. This divide is even starker when considering the top researchers in each group.”

The team of four has obviously put a good deal of time into the study which was contributed for publication by Stephen Schneider (pictured). Why bother, one might ask.  Surely it’s all too apparent. It may be to readers of Hot Topic but the study notes that considerable and even growing public doubt remains about the anthropogenic cause and the level of scientific agreement about the role of anthropogenic greenhouse gases in climate change. The vocal minority of researchers and other critics who contest the conclusions of the mainstream scientific assessment has received large amounts of media attention and wields significant influence in the societal debate about climate change impacts and policy.

An analysis such as the study offers has not been conducted before, and the writers observe that it can help inform future ACC discussions. Translated into common parlance I guess that means they hope this will put paid to the idea still abroad, in at least the American media, that denial of anthropogenic climate change retains a respectable level of scientific credibility.

That may be optimistic. Journalism in general still has difficulty getting its head around the reality of mainstream climate science. The idea that there is a realistic alternative shows remarkable persistence. When I was writing occasional columns for my local paper, the Waikato Times, I discovered that my attempts to explain aspects of the current science eventually came up against an anxiety that the paper was not presenting a balanced picture. There was finally talk of pairing my column with another which would meet the paper’s obligation to offer its readers more than one opinion. I protested that I was representing mainstream science and asked why the paper should feel that needed to be balanced. I made that my last contribution and escaped the indignity of a balancing viewpoint. It seemed fairly clear that the East Anglia emails and the baseless attacks on the IPCC report by the likes of Jonathan Leake were enough to unsettle the journalists with whom I was dealing and bring back to life concerns which I thought had long been laid to rest.

One nevertheless hopes that  surveys and appraisals such as this one in a highly regarded journal will make a difference to media perception and help establish in the public mind the seriousness of the scientific understanding and predictions. It seems inconceivable that we should continue much longer refusing to face the reality.  But I’ve been thinking that for four years now.