Revenge of the rainforest
The Amazon has long been the lungs of the world. But now comes dramatic evidence that we cannot rely on it in the fight against climate change
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Independent Minds
It covers an area 25 times bigger than Britain, is home to a bewildering concentration of flora and fauna and is often described as the "lungs of the world" for its ability to absorb vast amounts of carbon dioxide through its immense photosynthetic network of trees and leaves.
The Amazon rainforest is one of the biggest and most important living stores of carbon on the planet through its ability to convert atmospheric carbon dioxide into solid carbon, kept locked in the trunks of rainforest trees for centuries.
But this massive natural "sink" for carbon cannot be relied on to continue absorbing carbon dioxide in perpetuity, a study shows. Researchers have found that, for a period in 2005, the Amazon rainforest actually slipped into reverse gear and started to emit more carbon than it absorbed.
Four years ago, a sudden and intense drought in the Amazonian dry season created the sort of conditions that give climate scientists nightmares. Instead of being a net absorber of about two billion tons of carbon dioxide, the forest became a net producer of the greenhouse gas, to the tune of about three billion tons.
The additional quantity of carbon dioxide left in the atmosphere after the drought – some five billion tons – exceeded the annual man-made emissions of Europe and Japan combined. What happened in the dry season of 2005 was a stark reminder of how quickly the factors affecting global warming can change.
"For years, the Amazon forest has been helping to slow down climate change," said Professor Oliver Phillips, from the University of Leeds and the lead author of the study in the journal Science. "But relying on this subsidy from nature is extremely dangerous. The emission of five billion tons of carbon dioxide was huge. It meant that a major part of the biosphere had switched from one function to another, from a carbon sink to a carbon source.
"It shows what could happen if droughts become more frequent, and climate models suggest that Amazonia will get warmer and so put more water stress on vegetation. If the Earth's carbon sinks slow or go into reverse, as our results show is possible, carbon dioxide levels will rise even faster. Deeper cuts in emissions will be required to stabilise our climate."
The study, which involved nearly 70 scientists from 13 countries, examined more than 100,000 trees in 100 forest plots. The scientists had been monitoring changes to the girth of each tree over a period of between 20 and 30 years, so were able to calculate with some precision the effect of the 2005 drought on tree growth.
The drought itself was unusual. Normally, droughts in the Amazon are the result of changes caused by El Niño, the warm Pacific Ocean current, but the one in 2005 was a result of higher-than-average temperatures at the sea surface of the tropical North Atlantic.
"The pattern of the drought was shorter but sharper and more intense than usual," Professor Phillips said. "It affected the southern two-thirds of Amazonia and especially the south-west through reduced rainfall and higher-than-average temperatures. It was the kind of drought we expect to see in a globally warming world. On the ground, it was hard to see because you had to detect by measuring lots of trees over a larger area of land. There was not a massive die-off of trees."
The researchers found that the drought sharply reversed the decades-long growth of the trees. The normal die-off rate of the trees, about 1 per cent per year, doubled to 2 per cent, and the continued expansion of tree girths effectively stopped.
"Visually, most of the forest appeared little affected, but our records prove tree death rates accelerated," Professor Phillips went on. "Because the region is so vast, even small ecological effects can scale-up to a large impact on the planet's carbon cycle."
Humans worldwide are estimated emit about 32 billion tons of carbon dioxide each year but just less than half of this, about 15 billion tons, remains in the atmosphere. The rest is absorbed by natural carbon sinks in the ocean and on land.
Scientists have calculated that the world's tropical forests collectively absorb about 4.8 billion tons of carbon dioxide every year, with the Amazon being the single biggest rainforest sink. Amazonia alone is estimated to store about 100 billion tons of carbon locked up in its trees.
This is why the climate change negotiations in Copenhagen later this year will focus heavily on what can be done to save rainforests to ameliorate the effects of man-made emissions of carbon dioxide.
Lee White, the chief climate change scientist for the government of Gabon, said: "To get an idea of the value of the sink, the removal of nearly five billion tons of carbon dioxide from the atmosphere by intact tropical forests, based on realistic prices for a ton of carbon, should be valued at about £13bn a year. This is a compelling argument for conserving tropical forests." Dr White was a co-author of another study last month on the role played by African tropical forests in processing carbon dioxide.
Professor Phillips added. "It's surprising to see how sensitive the system appears to be. This is the first time anyone has tried to measure the impact of a big tropical drought on the ground. Now we've quantified it and, yes, there's a specificity there and it wouldn't take a huge change to shut down this thing and switch it to an overall source of carbon dioxide."
The Amazon: Facts and figures
* The Amazon rainforest covers an area of some 600 million hectares (2.3 million sq miles), an area of land 25 times bigger than Britain. It is the biggest rainforest on Earth, responsible for about 40 per cent of the world's rainforest absorption of carbon dioxide.
* Satellite surveys indicate that about 5,800 sq miles of the Amazon rainforest is burnt or cleared each year to make way for cattle ranching, farming or other kinds of development.
* More than half of the world's estimated 10 million species of plants, animals and insects live in tropical rainforests. One-fifth of the world's fresh water moves through the Amazon basin.
* Scientists estimate that there are at least 100 billion tons of carbon stored in the trees of the Amazon rainforest and each year the Amazon absorbs about 2 billion tons of carbon dioxide from the atmosphere.
* During the extreme drought of 2005, the Amazon became a net producer of carbon dioxide, releasing an estimated 3 billion tons of the greenhouse gas into the atmosphere – a net increase of 5 billion tons.
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Comments
How much is a life worth or how much is civilisation worth?
Of course it won't happen - what will happen instead is massive overpopulation which will lead to conflict, war, misery, and environmental and human disaster - which will limit the population anyway in the long run. James Lovelock is right - nature will cull us eventually. Sadly, only emergency action will work now, with 6.8 billion people in the world - it was 3.5 in the 60s - and 1.5 in the 20s (the maximum the earth can sustain). We should all pray for a new disease that leaves people sterile. Otherwise, we're toast.
AS A MEMBER OF MANY OF THE GROUPS WHO HAVE BEEN WARNING THE PEOPLE OF THIS PLANETS STATE, NATURE HAS BEEN GIVING US WARNING SIGNS FOR YEARS BUT THE GREEDY AND LABOTOMISED PEOPLE OF THIS WORLD INCLUDING SCIENTISTS WHO HAVE KNOWN WHAT HAS BEEN GOING OF FOR OVER 40 YEARS HAVE IGNORED IT HOPING IT WILL GO AWAY.
THE RAINFORESTS HAVE PROVED THAT NATURE STILL HAS THE UPPER HAND AND THAT WE THE HUMAN RACE IS A VIRUS IT WILL CERTAINLY FIND A CURE FOR, IF WE DON'T BUCK UP OUR IDEAS AND BEGIN TO TREAT NATURE WITH THE DEEP RESPECT IT DESERVES. UNFORTUNATELY IT WON'T MAKE THE DIFFERENTIATION OF THE PEOPLE WHO HAVE BEEN TRYING THIER UTMOST TO HELP THE PLANET GET TO A BETTER AND CLEANER PLACE, SO WE WILL HAVE TO SUFFER FOR THIER STUPIDITY.
THE COUNTDOWN TO OUR DESTRUCTION IS GETTING FASTER WE ARE HEADING TOWARDS ZERO AT THE RATE OF KNOTS, WE ARE ALREADY WELL OVER THE TIPPING POINT AND BAD THINGS ARE GOING TO HAPPEN, BUT WE CAN STILL MOVE TOWARDS MAKING THINGS RIGHT IF PEOPLE JUST START CUTTING THEIR CAR, PLANE AND SHIP JOURNEYS AND LIVE IN A PLANET FRIENDLY WAY.
MY PREDICITON IS THAT ONLY A GIANT CATASTROPHY WILL BRING THIS PLANET TO REALISATION OF WHAT SOME OF HAVE DONE. IT IS A SHAME THAT LIFE HAS TO BE LOST FOR THE WAKE UP CALL.
Yep, feed the hungry hoards/ catholic nations/ whoops sorry/ billions of bodies who need feeding/ whoops/bio fuels/ 4x4s/ school run/ who cares really?
Governments are not capable of intellectualising these problems/ their role is to collect taxes and keep civil harmony and insure the population stays like a proverbial fat termite mound.
KEEP 'EM FAT , WELL FED and HAPPY!
Does anyone think the same as me that we all share responsibility for our planet. Valuable irreplacable resources that help keep the climate stable should not be the sole responsibility of the particular country they happen to be in. They belong to the planet, and therefore to all of us.
The damage caused by ignorance and economic greed surpasses everything that has happened in the past long ago. China and India and Indonesia and other countries are poisoning the atmosphere, as we did during our industrial revolution. Altogether now, we should all shriek abit more. The rainforest will vanish and then there will be desert.
Actually we are all well and truly stuffed and it is too damned late.
Unless the forest is allowed to grow for ever (impossible), it will always reach a point where the carbon absorbed will equal the carbon generated.
The simple fact is that too many people are alive right now.
One trusts that a different class of leader aspires to both political and business leadership. Present circumstances are the sum accumulation of precedent conditions and past decisions.
Numerous pressure points now converge to a place called the immediate future. Expect things to get worse. You cannot negotiate with Nature.
Jack Smith . . . Australia
Sure, it might be too late to do something about the climate. But then again, the climate would have changed anyway, with or without our help.
Look at the geological history of our world. Nothing will ever stay the same. That's a basic truth we need to understand.
The question that should really concern us, is HOW can we stabilize the climate in such a way it's beneficial to as many of earth's inhabitants as possible.
The CO2 question is not irrelevant as such, but it oveshadows more fundamental questions. I feel like many people here that CO2 reductions are a plight. There are too many reasons why we do not want to increase the levels of a biologically active gas without being sure what the consequences will be. That's a pure ethical matter. In that respect our politicians have allowed Big Industry to act unethical. And those smart scientists developing technology to produce all those GHH's, should have shown their concern earlier and in a more audible and visible way.
30 years ago I had the same concerns as today. There were many people who already then warned that consumption patterns and use of fossil fuels would eventually harm our planet. So don't pretend that it's the latest revelation for which we need to thank Mr. Gore. We thank him anyway, because he put the climate on top of the agenda.
But to those commenters who are shouting out loud about that it's too late anyway, and now we can expect nature's revenge to hit us badly. Might be true, but it is not really helpful.
What you in the UK need to do, is to remove those politicians that show arrogance and negligence towards nature in the next election. And refuse to use your car so often, instead demanding better public transport. Small things. Stop eating all that red meat. Your body doesn't need it anyway.
Put your money where your mouth is.
And most of all, do this entire planet another small favour. Stop talking about CO2 storage. Stop talking about nuclear energy. Do whatever you can to use renewables for power production. Start talking with Iceland NOW. They have plenty of geothermal energy. Become part of a larger european initiative to start developing the Sahara for production of solar energy. All this needn't be too complicated. But you need to act now.
And cheer up, man. If it's too late anyway, you better enjoy yourself as long as it lasts. Keep smiling!
Please realise also that sheep, cows, horses, chickens, pigs would not exist in their present form without meat-eating and farming, and nor would the countryside - which was formed by farming and is now managed by the same.
And you force your family and children to follow your religion of veganism too. Like some evalgelist religious nutter. You eat crap if you want - but you are NOT superior to anyone in terms of health (a vegan diet is boring and 50% of veggies are deficient in iron - red meat is the best source - and you have to take supplements of B12 which PROVES your diet to be unhealthy and unnatural). Not giving children meat and a varied balanced diet is child abuse and you sholuld be ashamed of yourself for abusing your children. Veganism is a lose-lose situation for yourself and the planet.
Of course, as a breeder - a parent - you are damaging the planet far more than anyone who is childless. Why did you have children for selfish greedy reasons? If you're that responsible, you wouldn;t have bred and inflicted your spawn on the overcrowded planet. Making the selfish decision to breed means putting your own selfish interests over the planet you hypocrite.
Also I would not say that the life of modern day farm animals is anything to be envied, in fact many would describe it as a short time of great suffering. The forests in Brazil are being destroyed to breed cattle and to grow soy to fatten European livestock and we all know the methane produced by these animals contribute enormously to carbon emissions. I am certainly not trying to preach to anyone but it is it not good to hear both sides of the story?
And please stop talking crap. You can eat whatever diet you like - and if you want to starve yoursle fto death I don't care - but do NOT vomit out second hand intellectual puke by the occasional idiot academic. The vitamin B12 deficiency is well researched and documented. Moreover, I do not care what some Swede nutter academic says - the fact is, as the vast majority to sceintists and doctors would assert, the human body evolved to be omnivorous. THAT is why we have our digestive system, the teeth we have and the eyes on the front of our heads. Apes eat fruit but also eat meat.
Many doctors would say some meat is healthy - red meat is the best source of iron (a small steak equals 10 plates of spinach - your body does not absord most of the iron in that) - and should be part of a balanced diet. It is natural to eat meat - your lifestyle is artificial, faddish and unnnatural. Over 50% of vegetarians are deficient in iron and B vitamins, and most of those with anorexia start their journey by becoming veggie. It is NOT healthy. But you are free to eat what you want of course - just don't try and justify your diet with dubious and spurious views of crackpots.
Meat-rearing farming is the only reason the countryside in managed properly.
The forests are being destroyed because of overpopulation. The methane produced by cattle is insignificant actually.
Also, vegans and veggies are always so smug and self-righteous - like evangelical religious people. Fact is, your diet is not superior -in fact, it is inferior to a balanced diet that includes meat - as proven by the large number of veggies with iron and vitamin deficiencies.
Honestly said, I am NOT a vegetarian. I never said I was either. You accused me of being one, which is completely wrong.
I eat fish and pounltry. Though I would like to reduce my intake. I basically like animals too much to justify killing them.
But the point I tried to make with my call for eating less red meat, was one many scientists have made too. We just destroy too much of our planet in order to enable too many of us to eat hamburgers and steaks on a daily basis. It is basically unethical not to want to change this.
I don't want to refuse you your weekly steak, but don't try to justify eating red meat each and every day by some rather misinformed notions about being vegan. Because vegetarians that chose their diet carefully, don't seem to have any kind of deficiancy. Which you admit implicitly, by stating that only 50% of the vegetarians don't seem to be able to follow the right diet. So, 50% still manages. So, why the demand for red meat?
In the light of developments in modern technology, I predict that within 50 years we actually don't need animals at all to produce a good steak. We use gen technology to get it done in a test tube...
In addition the respected Center for Research on the Epidemiology of Disasters have repeatedly stated in reports that there are many other factors unrelated to climate with regard to increase reportage of natural disasters.
The news here is that rain forests, world wide, endure short, sharp droughts - a natural event. They have done so in the past and will do so in the future.
Industrialisation permitted the pumping of water out of coal mines to feed further insutrialisation, which led to use of petroleum. Use of petroluem led to industrilisation of the food system -the so-called Green Revolution (which was entirely dependent on mechanisationa and industrial fertilisrs etc. so would be better described as a black revolution). Without the additional food that use of oil permitted, the wolrd population would never have reached its current levels.
As for projections of the world population rising to 10 billion, that is just pie in the sky, since the oil supply has peaked and is in decline, so the food will not even be available to maintian the current population. Widespread starvation is on the hoirizon even before we factor in the severe or abrupt climate change that is on its way.
The fact is we are at the point of the greatest discontinuity in human history, yet the bulk of the population is completely clueless about itv all.
I don't understand why politicians and people STILL don't act now that it's not even our grandkids' or kids' lives that are in danger but our own. I could see some folk were too selfish to care about future generations, but now that everything has speeded up ... why the lack of action? I just ... I can't understand it. I mean, even politicians and oil barons must want to live, surely?
It's like sitting on the flipping Titanic going "captain, please, there's an iceberg over there".