I was going to entitle this little web log post “Yet More Proof Journalists Can’t Read” but I thought that might seem a little too rude, and anyway, I wanted to be clear about the subject of the content of the post in the title, so I changed it.
I have just received an e-mail from Jonathan Leake of the Times of London and the Sunday Times. By order of his e-mail signature, I am not permitted to share entirely the contents of that e-mail with you, however, I can relate to you that it concerns the latest Climate Change “sceptic” bunkum story, to which you can find extensive reference plastered all over the Internet like some ugly, testosterone-fuelled teenage graffiti :-
“Amazon rain forests were unaffected from once-in-a-century drought in 2005 : Friday, March 12, 2010”
“New Study Debunks Myths About Vulnerability of Amazon Rain Forests to Drought : ScienceDaily (Mar. 12, 2010)”
“Another WWF assisted IPCC claim debunked: Amazon more drought resistant than claimed : 11 03 2010”
“Never Mind The Hype – Amazon Unaffected By Recent Drought : Thursday, March 11, 2010”
The history of this research is that in 2007 a paper was published that concluded that there was a “greening up” of the Amazon rainforest basin during the unprecedented drought of 2005 :-
The conclusion was that, “2005 drought “green-up” is unlikely to be an artifact, but a real indicator of forest productivity”, and that this could be down to the increased sunlight (due to reduced cloudiness, which had led to the reduced rainfall) during that particular period.
However, further work on “greeniness” of the Amazon duing the outstanding drought of 2005 has showed the 2007 results cannot be reproduced, as quoted by ScienceDaily :-
“A study published in the journal Science in 2007 claimed that these forests actually thrive from drought because of more sunshine under cloud-less skies typical of drought conditions. The new study found that those results were flawed and not reproducible.”
In summary, “[the new] NASA-funded study has concluded that Amazon rain forests were remarkably unaffected in the face of once-in-a-century drought in 2005, neither dying nor thriving, contrary to a previously published report and claims by the Intergovernmental Panel on Climate Change…The comprehensive study published in the current issue of the scientific journal Geophysical Research Letters used the latest version of the NASA MODIS satellite data to measure the greenness of these vast pristine forests over the past decade.”
“Amazon Droughts and Greening : 09 March 2010 : The sensitivity of Amazon rain forests to dry season droughts is still poorly understood, with reports of enhanced tree mortality and forest fires on one hand, and excessive forest greening on the other. In a current story there is a report that previous conclusions of large scale greening of the Amazon as a result of drought are not reproducible. Approximately 11%-12% of these drought stricken forests display greening, while, 28%-20% show browning or no change, and for the rest, the data are not of sufficient quality to characterize any changes. These changes are also not unique; approximately similar changes are observed in non-drought years as well. The Amazon drought of 2005 was the worst ever recorded in the Amazon. The drought has turned rivers into grassy mud flats, killed tens of millions of fish, stranded hundreds of communities, and brought disease and economic despair to the region. There have been other droughts such as in 1926, 1983, and 1998. These other droughts can be more linked to El Nino effects. Scientists are not certain as to the cause of the 2005 drought, although warmer water temperatures in the Atlantic Ocean are the leading suspect. Wet tropical forests are the most species rich biome, and tropical forests in the Americas such as along the Amazon River are consistently more species rich than the wet forests in Africa and Asia. As the largest tract of tropical rain forest in the Americas, the Amazonian rain forests have unparalleled biodiversity. However extensive deforestation has occurred in the last few decades and the 2005 drought did not help. There had been earlier claims that the 2005 drought caused a “greening” of the Amazon. Tied to this thought was that available sunlight increased in this area. In the March Geophysical Letters an article was published by several authors entitled: “Amazon Forests Did Not Green-up in the 2005 Drought”. The authors included Arindam Samanta and Ranga B. Myneni. In this the authors concluded that only about 10% of the affected area increased in greenness and about three times this ares became browner. The majority of the affected areas could not be determined. At the same time sunlight (in the wavelengths most useful for plant life) decreased rather than decreased in most areas. There was no co-relation between drought severity and greenness changes, which is contrary to the idea of drought induced greening. Finally the study concluded that the spatial patterns of Enhanced Vegetation Index changes seen in drought year 2005 are not unique in comparison to non drought years. Original abstract : https://www.agu.org/pubs/crossref/2010/2009GL042154.shtml “Amazon forests did not green-up during the 2005 drought” ”
However, as always in Science, one report is not the end of the story, nor even the whole story.
What does “greeniness” show ? That vegetation in the Amazon was growing during the 2005 drought, and has been growing since. What it does not show is whether there have been any permanent changes due to the drought that could affect the long-term survival of this massive rainforest.
Another satellite monitoring project, or rather, twin satellites, known as GRACE, has been producing other information on this vital Carbon Sink :-
“2005 drought event in the Amazon River basin as measured by GRACE and estimated by climate models”
This research has shown that special attention must be paid to the kind of water in the basin and how water runs off the basin, when constructing Climate models.
There has also been unchallenged work on the loss of biomass in the Amazon rainforest during the 2005 drought :-
“Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 × 1015 to 1.6 × 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change…”
“Relative to the predrought sink, we estimate a total impact of –1.21 Pg C (–2.01, –0.57) by simply scaling the per-plot impact by the total droughted area (~3.3 × 108 ha) and assuming that nonmeasured components of biomass were equally affected. Scaling the per-site impact yields slightly greater values (20). Alternatively, we can scale the observed relationship between relative biomass change in plots and droughting (Fig. 2) by the moisture deficits across Amazonia estimated from remotely sensed rainfall data (19, 20). This suggests an even greater impact on the biomass carbon balance of the droughted area: –1.60 Pg C (–2.63, –0.83). Site-based scaling up indicates similar values (20). Although better understanding of soils is needed to determine the local effects of meteorological drought, the magnitude and consistency of these estimates demonstrate Amazonia’s vulnerability to drought and the potential for changes in tropical climates to have large carbon cycle impacts. Our on-the ground data reveal that, despite apparent “greening up” during dry periods (13, 14), Amazon drought accelerates mortality over large areas (Fig. 2B) (20).”
The Amazon drought of 2005 was part of a longer drying out in the rainforest which has caused extensive and probably permanent change :-
“…The impact and the severity of the long-lasting 2002–2005 drought can be clearly seen in several other important hydroecological indicators (figures 3–6). The Amazon streamflow measured at Obidos (captures rainfall from about 90% of the total Amazon drainage basin) shows an unusually long and slow decrease since 2000, culminating in late 2005, a trend consistent with the precipitation anomaly…The recent drought in the Amazon highlights the sensitivity of its hydrology and ecosystem to prolonged drought conditions, as opposed to large short-lived ones. The rainforest has adapted to seasonal and short-term drought by strategies such as water uptake by deep roots, but may be less resilient to longer term change. The recent IPCC AR4 climate model simulations predict rainfall reduction in the Amazon, possibly due to a combination of changes in the Pacific and Atlantic SSTs as well as overall warming-induced changes. Although the causes of 2005 drought and future scenarios may differ, similar impact mechanisms likely underly the risk of possible alteration to the Amazon ecosystem and carbon cycle…”
The Amazon still looked green and healthy during and after the major drought of 2005, but had lost part of its living mass.
So there you have it : journalists do not understand what they are reading. Green tree canopy does not mean that things haven’t fundamentally changed in the rainforest as a whole.
It’s this insight that is so fundamentally important.
It is for this reason that all journalists should study Climate Change Science.