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Ripples from the rainforest

Updated Monday 30th November 2009

Uncover the changes going on in the rainforest – and the impact they’re having on our climate. Professor Yadvinder Malhi, from the Environmental Change Institute Oxford, shares his insights at the Oxford TippingPoint Conference.

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Copyright The Open University


How does your work relate to climate change?

My work is particularly focused on how ecosystems and tropical forest ecosystems in particular are responding to climate change and how managing these systems can be part of a strategy of dealing with, with adapting to and mitigating climate change. So to dive into that a bit further I’m interested in understanding how rainforests such as the Amazon are responding to atmospheric change, are they increasing in biomass, are they increasingly vulnerable, is there a risk that the Amazon will start dying back and turning into savannah at some stage. And at the same time we know that tropical deforestation in particular is contributing towards climate change as well as causing biodiversity loss, and I’m interested in both understanding that contribution but also then understanding how can we build mechanisms to slow down deforestation that can help us adapt to climate change and mitigate climate change.

What are you planning over the next year?

On the side of understanding the response to climate change we have two main strands. One strand is monitoring forests right across the tropics. So, for example, in the Amazon we have a hundred sites where we’ve been monitoring forests for the last two decades. Where we document what the trees are, how they’re growing and how they’re dying, what the species composition of that forest is and how that is changing over time. And this network now extends over ten countries in South America, but also we have similar networks spreading in Africa and in Asia. And that is showing some really interesting insights.

It’s showing that the forests in the short term have been increasing in biomass, possibly as a response to increasing atmospheric carbon dioxide, and in that sense have been acting as a brake on global climate change by absorbing a fraction of the CO2 emissions that human activity causes. At the same time there’s evidence that this brake won’t last for long, there’s strands of evidence that this brake won't last for long. There’s evidence that this carbon sink is slowing down, and there’s evidence that drought in particular may cause this sink to turn into a source, and this brake could turn into an accelerator in the near future. So we’re trying to understand what the thresholds are for these phenomena.

So a lot of this long-term monitoring is having intensive experiments where we actually try and manipulate tropical forests to understand when they’re pushed out of a normal situation, how they work, understanding the mechanics of forests. So one example is, in Brazil we’ve been droughting a hectare, a hundred by hundred metre area of rainforest, since 2002, taking half the rainfall out to simulate what the climate of the EasternAmazon may be like by 2050. And then trying to understand how resilient or vulnerable the forest is to this drying circumstance. Similarly we’re doing other experiments in the Andes of Peru where we’re moving soils and plants down slope to simulate warming, climate warming, and trying to understand how the ecosystem responds to that warming, how the stocks of carbon in the soil for example respond to that warming.

How long before you get results from the experiments?

The experimental work starts yielding results within a few years, two to three years, and monitoring work has started becoming very powerful after ten years. We’ve been going for over ten years and now it is giving us powerful insights. So, for example, in 2005 there was a strong drought in Amazonia, and because we had this monitoring network in place we saw this carbon sink flip to a carbon source in that year and then flip back to a carbon sink the following year. And one possibility is that this flipping which happened in 2005 was the first of a series of flips that may occur over the coming decade. And we have the observation system in place to try and watch these processes as they occur. And at the same time it’s also an early warning system.

There will be changes going on that we don’t suspect at all, changes in the ecology, ecosystem composition, and by having this long-term monitoring going on we will pick up the first clues to the unexpected and I’m sure there’s going to be unexpected things happening. Our research network is fundamentally rooted in lots of people getting muddy and sweaty out in the forests. So we have an army of, say in southern Latin America, we have an army of twenty or thirty students who are out every month spending two weeks of every month in the forest collecting the primary data. And our work as coordinators is to train people, to standardise techniques, to encourage consolidation of this data, and to encourage this army of students to also publish these data and also further their progression as scientists.

Informing public policy over the next 10 years. What do you hope for?

There are two sides to the things that I’m hoping for. One is on this side of understanding what the thresholds are for critical ecosystems like tropical rainforests or other ecosystems, and therefore if we can give them early warnings that if we dry the Amazon by so much or if it gets warmer by so much then we’ll reach some irreversible thresholds, which could be extremely dangerous. It may shake negotiators or policymakers out of complacency that we can negotiate for a two-degree world or a four-degree world and give some hard edges and some lines in the sand to help inform that process.

The other thing that makes this coming decade perhaps the most important for tropical rainforests this century is to do with the importance of slowing down deforestation as one strategy to tackling climate change. And it’s been recognised for decades that deforestation is both a problem in terms of biodiversity, in terms of unsustainable development, just wasting land and resources in a blind, short-sighted sort of mining off the natural wealth of many tropical countries. But there has been no way of really changing the drive to clear these forests and slowing that down. Climate change as well as being a major threat ironically provides an opportunity to provide the resources required to start tackling the threat of deforestation. And the way it does that is by providing a value, in terms of carbon value to these forests that people particularly in rich world countries and rich world industries are willing to pay to see those forests in place and to pay the potential deforesters of that land.

So I’m very optimistic that either at the UN Climate Conference in Copenhagen in December this year, or in the year afterwards, some international agreement will be made to support the slowing down of deforestation or at least provide the resources that are needed to instigate that process. However, if there is a political agreement or even a financial agreement that is only the beginning of the process, the real challenge then begins. We have these resources, how do we tackle forest conservation and slowing down deforestation in a way that is effective in these, often these remote and lawless frontiers, that’s ethical, that takes into consideration the needs of the users of the forest, the needs of developing countries, and is efficient, that works on the timescales that we need it to work in terms of the climate’s emergency.

And so I think given that in the next year we expect some sort of deal on tropical forests and climate change to come through the UN process, the next ten years are when a deal turns from being a political process to a manifestation on the ground with pilot projects, with test demonstrations, with failures and successes, and they’ll emerge over the next five and ten years, what works and what doesn’t work.

Where does the passion come from?

I think, apart from being passionate about ants in my garden as a child and just sort of being fascinated by the simple nature of my garden, I actually started off my intellectual career wanting to be an astronomer, and I started off as a physicist. And realised very early that I enjoyed, I went on little field trips, and I enjoyed being surrounded and immersed in the topic that I was studying rather than having it in a microscope or behind a computer screen. And that, I realised instinctively, emotionally that was the thing that satisfied me the most, and I still get that kick and buzz every time I walk in to a rainforest that I’m just surrounded by this vast, mysterious organism around me.

The other key factors were, in the final year of my undergraduate when I was looking for ways of using my skills as a scientist, I was reading the books of James Lovelock and realising that these ideas, whether those specific ideas are correct or not but this theme and this subject area had huge potential and was of immense importance, and yes that was an area that I wanted to make a contribution to and to try and understand how this earth system functions, the role that life plays in this earth system, and how it’s going to evolve over this coming century and beyond. And so that was a pivotal moment.

Optimism or pessimism?

I think whether somebody’s optimistic or pessimistic about a problem I feel is more driven by their personality than it is by facts. So in my case I feel I naturally fall towards the optimistic end of the spectrum by my nature. But then if I can find some facts to justify my optimism, I find that in the area of tropical forests there are huge opportunities now for slowing down deforestation that hadn’t existed in the past.

And taking my example from the Amazon, in particular, as Brazil got to grips with the challenge of managing the Amazon and the importance of sustaining the Amazon, it has used science along with other factors in coming up with a programme for slowing down deforestation in Amazonia, and so the deforestation rates in the Amazon are 60 per cent lower now than they were three years ago. And the target that Brazil has is to bring them down even much further over the next decade.

And our role as engaged and active scientists is to support that process, to encourage, provide the scientific facts that help support that process, to encourage that process along and also to build a capacity for science in countries like Brazil but now lots of other countries with less capacity such as in Sub-Saharan Africa so that engaged scientists within those countries can drive these agendas forward. And I think in the case of Brazil one huge influence has been that there is an engaged environmentally aware scientific community that’s been trained up through the interactions and research that begun in the 1980s on the environment of the Amazon.

So the model of Brazil actually gives me a lot of hope that there are ways of changing the direction.





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