Welcome
to my homepage! I am a researcher at the faculty of
Earth and Life Sciences of the VU University (Vrije Universiteit), Amsterdam,
Netherlands
Within the faculty, I aim to increase our knowledge of carbon exchanges between the terrestrial biosphere and atmosphere on continental and global scales, with a special emphasis on fire and deforestation processes. The main research tools I use are remote sensing and biogeochemical modelling.
Most of this research originated when working at NASA Goddard Space Flight Center as a research assistant for Jim Collatz and Jim Randerson. We incorporated a fire module in the CASA biogeochemical model to better understand the role of fire in the global carbon cycle. This work led to my thesis which I defended in 2006 at the VU University Amsterdam. Besides further improving this module, I also aim to quantify deforestation emissions -one of the largest uncertainties in the global carbon cycle- and I try to better understand the role of climate in explaining spatial and temporal patterns in fire activity.
Some research highlights:
- The global amount of carbon combusted through fires is 2.5 Pg C year-1, or about 30% of global fossil fuel emissions. more...
- Net emissions (stemming from deforestation) are about 0.6 Pg C year-1, but uncertainties are large
- In Indonesia, it takes both drought and humans to create large fire events. Droughts are triggered by variations in ENSO and the Indian Ocean Dipole (IOD). English..., Dutch...
- Fire emissions in Indonesia are comparable to emissions from fossil fuel combustion. Due to the relation between drought and fires here, and the projected increase in drought events this link may indicate a climate-carbon feedback English..., Dutch...
- Despite the importance of socio-economic factors, the amount of deforestation is for a substantial part driven by climate, with important implications for future deforestation rates. more...
- Interannual variability of fire emissions is large, especially in deforestation regions, and could explain about 2/3 of the interannual variability in CO2 growth rate over 1997 - 2001. more...
For this work I received the Vening Meineszprize from NWO in 2008
Nature Geoscience paper on role of deforestation in the global CO2 budget
We just published a commentary in Nature Geoscience which may have some important implications for ongoing discussions how to include reducing deforestation in the follow-up of the Kyoto protocol.
We basically redid the IPCC calculations that are the basis of the most widely cited numbers for the contribution of deforestation and forest degradation to total anthropogenic CO2 emissions. While the IPCC numbers were based on the best information available during that time, since then:- some deforestation studies have lowered their estimate
- fossil emissions have increased substantially.
This obviously lowers the ratio of deforestation and forest degradation to total anthropogenic emissions. When following the same IPCC methods we found that deforestation and forest degradation would nowadays (2008) account for about 12% of total CO2 emissions instead of the 20% often assumed, or 10% of total greenhouse gas emissions.
But there is more to the paper! Deforestation-related emissions from peat degradation in the tropics was not included in one of the IPCC approaches. If REDD becomes inclusive of this, it would boost the contribution to 15% of total global CO2 emissions (or 12% of total global greenhouse gas emissions) and the total emissions estimate (deforestation, forest degradation, and peat degradation) would be equal to the previously used emissions number for deforestation and forest degradation. In other words, this way the lower contribution (15% instead of 20%) would be solely due to increased fossil fuel emissions. Please keep in mind though that all these numbers have a large range of uncertainty, easily 50%.
The main conclusions of the paper are that:- New climate treaties will be more effective when the emissions from peatlands are included as a reduction option in addition to reducing deforestation and forest degradation.
- Reducing deforestation and forest and peatland degradation is no substitute for lowering global CO2 emissions from fossil fuels like coal, although it remains an important opportunity for many developing countries to reduce their greenhouse gas emissions and protect existing carbon stocks.
Some media coverage:
- Economist
- Time magazine
- according to the article our work indicates that "the problem of deforestation is becoming a lot less dire than previously thought". Hmmm, not so true, I have invited the author of the Time magazine piece (Bryan Walsh) to point out where we argue that deforestation is not so much of a problem anymore, but unfortunately he never get back to us. We highlighted that the contribution of deforestation to total emissions is lower now than it was previously (both due to downward revisions of deforestation estimates and increased fossil fuel emissions) but that the emissions are still a large source greenhouse gases, for about 30 countries even a larges source than fossil fuel emissions.
- "Unfortunately, the study's findings couldn't be further from the truth. The authors' recalculation had less to do with a reduction in deforestation than with an unexpected increase in emissions from the burning of fossil fuels. Indeed trees are still being lost at an alarming rate, at about 13 million hectares per year as of 2005, according to the U.N.", Indeed, the increase in emissions from the burning of fossil fuels lowers the contribution of deforestation emissions to total emissions, which was one of our main messages.
- a very nice blog by Duke's dean Bill Chameides
- an article in the online Guardian that requires some corrections:
- according to the article our work "could undermine attempts to pay poor countries to protect forests as a cost-effective way to tackle global warming." This requires some nuance; in negotiations folks knew that deforestation estimates are uncertain, our work clearly shows the need to include forest and peat degradation to make REDD more effective. If this is achieved, then the total emissions are similar to the previously estimated ones for deforestation and forest degradation.
- "the 20% figure was based on inaccurate and out-of-date information" and "The study showed previous assessments exaggerated the rate of tropical deforestation", that may be true in hindsight, but was not the case when these numbers were established (some are actually based on our own work).
- The 'Trouw' newspaper (Dutch)
- REDD-monitor (!! great summary !!)
- Mongabay
One final note: while the focus of REDD is for a large part on reducing emissions as this enables putting a price-tag on forests, there are numerous positive other effects such as protecting remaining carbon stocks and preserving biodiversity. This should not be forgotten in the debate! By including all sources of emissions (deforestation AND forest degradation AND peat degradation), REDD can be made more effective in both emissions reduction and conservation goals. However, it will likely not reach the 20% we often hear, highlighting once more the need for substantial fossil fuel reductions.