Lessons from the past

As we are nearing the end of my blogging time, I thought it was best to look towards the future to try and understand how the Amazon rainforest and its people will change and adapt in the coming years.

The best way to understand the future is to look to the past, and that is why a paper by Botta el al. (2002) interested me. It highlights the need to fully understand past climate and carbon fluxes in order to gauge what can potentially happen in the future. Botta and her team examine past climate records of the Amazon basin and in doing so discovered previously unseen modes of climatic variability, and long term carbon cycles seen in process based ecosystems models as a result of this.

These kinds of investigations are key to truly comprehending climate and carbon cycles on not only a regional, but a global level, and as such Botta et al.  urge fellow scholars to mirror their studies. Further studies are needed to understand the full mechanics of carbon models and identify sources and sinks to determine the true fate of anthropogenic carbon.

Focussing on the Amazon Rainforest, Botta et al.  demonstrate that even without taking into account anthropogenic carbon and land use changes the Amazon has experienced changes in its net carbon functionality, and since the 1930s alone has switched between being a net carbon sink and source, which can be seen in the figure below.

Demonstration of carbon fluxes as seen by Botta et al,.

What struck me about this article was the uncertainty it threw up in previous papers I had blogged about. For example the Malhi et al. article (which you can read my thought about here) even discussed their crude data, yet I didn’t comprehend how much variability an area could have in such a small space on time.

Another interesting, but very different type of historical analysis of the Amazon was conducted by Carnaval et al, (2008). By using models, Carnaval et al, were able to see the spatial range of forest under climatic scenarios of the present day, 6000 years ago and 21,000 years ago. In doing so, areas of stable forest were able to be delineated, giving me a small glimmer of hope for the future of the Amazon’s biodiversity and the people who survive on its land. Better than me explaining this to you, however, I urge you to give ita read.

So there we go, just a couple of different historical analyses to show you how much more work is needed to fully understand this awesome place. Yet with so many other of my blog posts, the word that springs to mind time and time again is ‘uncertainty’. 

Botta, A., N.Ramankutty, and J. A. Foley (2002) Long-term variations of climate and carbon fluxes over the Amazon basin Geophysical Research Letters 29,9

Carnaval, A. C., & Moritz, C. (2008). Historical climate modelling predicts patterns of current biodiversity in the Brazilian Atlantic forest. Journal of Biogeography, 35(7), 1187-1201.

Malhi, Y., J. T. Roberts, R. A. Betts, T. J. Killeen, W. Li and C. A. Nobr (2008) Climate Change, Deforestation, and the Fate   of the Amazon.  Science. 319 pp. 169-172