quarta-feira, 7 de setembro de 2011


African droughts are a well known and historical problem. The Sahel (left map), the vast territory south of the Sahara, for instance, has a long record of past droughts. So, every time you hear Al Gore talking about droughts, you should suspect some inconvenient truths are being omitted.

And that is the case with the Sahel droughts mentioned in the Climate Reality site above. It talks about the great Sahel drought, best known because of the "Do They Know It's Christmas" song. What it does not mention is that since then, the Sahel has been getting greener! The Global Warming Policy Foundation did an excellent briefing paper on this. But this is no news today, and National Geographic was already trying to explain the unexplainable two years ago!

Al Gore should know about it, so he will probably be switching his focus to the Horn of Africa, where a severe drought is underway. As can be seen by the map on the left (detail here), several areas of Somalia, Kenya and Ethiopia are experiencing famine or severe food shortage. The UNHCR has a special site on the issue.

While these droughts have caused some tens of thousands of deaths, and some 750 000 could die in the next four months, one would imagine that the IPCC would have predicted it. Think again! If you go to the IPCC page regarding the fractional change in precipitation changes over Africa in this century, you might find something shocking:

Now, if you're not familiar with Africa's geography, check it out again: the IPCC, in the Fourth Assessment Report, which gave them the Nobel Prize, is predicting a major rainfall increase, in the exact same region where the drought is underway! And I just can't get it, because these are predictions for a warming world. So, something must be wrong, very wrong, inside the IPCC and their 21 models... In Page 850, in the Chapter 11 Executive Summary, they summarize it:

There is likely to be an increase in annual mean rainfall in East Africa.

Then, in Page 869, in Chapter, things are even more clear:

The increase in rainfall in East Africa, extending into the Horn of Africa, is also robust across the ensemble of models, with 18 of 21 models projecting an increase in the core of this region, east of the Great Lakes.

Where did they get these predictions? AR4 references the work of Hulme et al. (2001) and Ruosteenoja et al. (2003). The first one is intitled African climate change: 1900-2100, and has a pretty interesting Figure 13, adapted in the first graph below. It shows a nice wetting trend for East Africa, for almost all the model simulations, and for the next decades (starting immediately). The second one is a Finnish report intitled Future Climate in World Regions: And Intercomparison of Model-Based Projections for the New IPCC Emissions Scenarios. It presents an intercomparison of climate changes projected for 32 regions on Earth, including Eastern Africa. Results are presented for seasonal temperature and precipitation changes between 1961–1990 and three time periods in the future centered on the 2020s, 2050s and 2080s. In the second graph below, for the period 2010-2039, most of the models show an increase in precipitation.

It gets worse. FEWS (Famine Early Warning Systems Network), which also has some very interesting data, was concluding last year:

The observed drying tendency is the opposite predicted by the 4th Intergovernmental Panel on Climate Change (IPCC ) assessment.

Further down the document, more detail is provided:

The observed rainfall tendencies are substantially different from the results presented in the most recent (4th) Intergovernmental Panel on Climate Change (IPCC) assessment (Christensen and others, 2007). Chapter 11 (Regional Climate Projections, Christensen and others, 2007) of the IPCC Working Group I report indicates that eastern Africa will likely experience a modest (5–10 percent) increase in June-July-August precipitation, a result our work, although not looking at the same months, suggests is unlikely.

Chris Funk, who works with FEWS, saw it coming, along with La Niña last year. In an article in Nature (registry needed) last month, intitled We thought trouble was coming, Chris gives an idea why this was mishandled:

The global climate models used by the Intergovernmental Panel on Climate Change were never intended to provide rainfall trend projections for every region. These models say that East Africa will become wetter, yet observations show substantial declines in spring rainfall in recent years. Despite this, several agencies are building long-term plans on the basis of the forecast of wetter conditions. This could lead to agricultural development and expansion in areas that will become drier. More climate science based on regional observations could be helpful in addressing these challenges.

This is the most important part. Not only has IPCC been useless in the last decade, but has been committing severe errors. But now, Horngate clearly shows us that IPCC has been contributing to several tens of thousands of deaths, because of inferior climate investigation, and misleading guidance. It is the time to shutdown an UN agency, that is doing more harm than good! And maybe, Al Gore will talk about all this inconvenience in a week...

[Edited 2011/09/09 to include citations from IPCC AR4 WG1 Chapter11]
[Edited 2011/09/09 to include citations from Hulme et al. (2001)]
[Edited 2011/09/09 to include citations from Ruosteenoja et al. (2003)]