Deforestation: Much Ado about the Contribution to Global CO2


CO2 is released from fires (red dots) like these near Lake Malawi in southern
Africa in
October 2009 for agricultural land clearing. Credit: NASA 

Deforestation. The environmental implications of the word are as numerous as the syllables. And scientists like Jim Collatz have the job of trying to ferret out and prove those implications. Or, as the case may be, of correcting what scientists have believed to be true.

When farmers or loggers chop or burn forest land, they set in motion the loss of biodiversity and habitat, as well as soil erosion. Collatz and other scientists are just as concerned — maybe even more so – with the carbon dioxide (CO2) deforested areas contribute to the atmosphere, warming the climate.

In 2005, the U.N. Food and Agriculture Organization announced that forest loss accounts for more than 20 percent of global emissions of CO2 from human activity. If we could stop cutting down trees, some argued, we could make a serious dent in the global carbon problem.

Not so much, a new study in the November 2009 issue of Nature Geoscience suggests. A group of Dutch and American climate scientists, including Collatz, assert that the UN’s estimate of atmospheric CO2 caused by deforestation is substantially overstated – by as much as 40 percent. Recalculating the 2005 figure with updated satellite-based estimates on carbon emissions, the researchers calculated the relative contribution of deforestation and forest degradation to be only about 12 percent.  

As a member of NASA Goddard’s Biospheric Sciences research team and co-author of the study, Collatz shared some of his thoughts with us.

What On Earth: How do you account for the change in the share of atmospheric CO2 from forest loss?

Collatz: New emission estimates from tropical deforestation are somewhat lower than in the past. At the same time, fossil fuel emissions are increasing rapidly. Deforestation is becoming a smaller proportion of total human-caused CO2 emissions. So, even if we could stop it completely, it would not be a substitute for decreasing fossil fuel emissions. If deforestation were 20 percent, then decreasing it to 10 percent may be significant and plausible. But since new analysis shows deforestation is closer to 10 percent, it’s unlikely that it can be reduced to zero percent.


What On Earth: What are the implications of your findings?


Collatz:  Some might read the paper and argue for less attention toward reducing deforestation. But we need to remain vigilant in this area. Forests provide other valuable services besides storing carbon: biodiversity, food, fiber, water resources, soil resources.  Even though current rates of deforestation may be lower than previously thought, vast amounts of carbon are stored in forests and soils all over the globe and are vulnerable to climate change and land management practices.  We need to monitor these carbon stocks and manage them for preservation and sequestration, or we may see unexpected increases in atmospheric greenhouse gases that go beyond what is emitted from fossil fuel burning.


To read the full paper on the Web, click here.

 –Gretchen Cook-Anderson, NASA’s Earth Science News Team

Correction: Please note the link above to the full paper has been revised. Co-author Robert Jackson of Duke University makes the paper available on the university’s site.

10 thoughts on “Deforestation: Much Ado about the Contribution to Global CO2”

  1. You know, what we have here is simply a larger version of Apollo 13…”Spaceship Earth” as it was called nearly 40 years ago. Trees are our planet’s CO2 scrubber system, and by reducing the number of trees, we reduce the capacity to remove CO2 from the atmosphere.

    We’re seeing the consequences of this today.

    Like the Apollo 13 astronauts, if we remove enough trees we can simply breathe ourselves to death!

    What set this process in motion? Some 35 years ago, Brazil made the decision to clear-cut the Amazon rain forest. Scientists warned that doing so could radically affect the composition of the atmosphere, but Brazil told the world to mind their own business and went about their merry way.

    Science does not respect politics…the simple fact is that if you want to remove CO2 from the atmosphere, we need more trees. Period.

  2. Another problem is the means of deforestation and where it happens most – in the tropics, where they use slash and burn. So not only do the trees go missing, they are burned, adding carbon and other gases as well as C02, then they raise beeves, adding more methane to the air and further degrading the land and starting massive land being carried off by run-off.

  3. I think the government should preserve and expand rain forests. It's very useful to clear up these Co2 spreading.

  4. -Dave H.

    While I do agree with the fact that “Trees are our planet’s scrubber system..” I do not agree with several other items in your post.

    How are we seeing the consequences of it today?

    Sure if we remove enough trees we could breathe ourselves to death, however that would take some time to remove the seeming endless miles of trees that cover many parts of the globe.

    Mainly it seems it is in 3rd world countries with rainforests (such as Brazil and in Africa) that have farmers chopping down acres of trees right and left for farming and cattle, not so much places like the US, Canada, Europe and Russia.

    While rainforests are significantly more valuable per square mile, it does not seem we will be running out of trees anytime in the next few centuries, however, rainforests do appear to be in much greater danger.

    Science does not respect politics? lol

    Take a look at the ‘global warming’ stories for that one, even though, I would have to say that is not true science.

    I would like to say however that Politics does not respect Science anywhere near what it should or things would be different on this and other issues for the better of the environment and humanity alike.

    (Except perhaps in 3rd world countries. Watch Avatar for that one.)



  6. The link on this article >To read the full paper on the Web, click here.< goes to a site that will only allow a login if you work at a
    company that donates to them or you make a donation. This makes the
    article useless.

  7. I too would like to read the full article, as it appears likely that deforestation is closer to 10% than 25%. The world Resource Institute last year has revised their figures used earlier by the FAO, in their latest chart to 11% see

    Deforestation should not be confused with sustainable forestry that can offer a real solution to reducing greenhouse gas by ensuring the forests and its products are valued higher than alternative land uses, creating jobs and wealth for local communities by regenerating harvested forests and value adding timber that becomes a carbon store.

    Whilst at least 10% of the world forests should be managed for protection of biodivesity, sustainable timber harvesting is the best way to slow deforestation and keep renewing the carbon store.

  8. Right moust Politicans don't care they look at 3rd part countries. but first we have reduce our CO2 from cars, factories and start using mor friendly energy resources.

  9. The problem is basic economics. Take a farmer in brazil who has a third of his land covered in rainforest. The revenue he can generate from the land is $1 per square metre, for the same square meter if he were to chop down the rainforest and use it for cattle grazing he could earn $4 per square meter.

    I think with deforestation it is just one of the many issues that needs to be resolved to help combat climate change. While it is more profitable to graze cattle rather than cultivate rainforest the brazilian rainforest will continue diminish.

    What did catch my eye recently was that a number of savvy brazilian farmers are joining an alliance to save the rain forest, they are doing this by letting a range european banks, funds and offset their carbon emissions by letting the rainforst grow back over old pasture, which is in fact earning them more than the cattle grazing. Change could well be on the horizon.

Comments are closed.