tirsdag 21. februar 2012

Climate change post 6: The Amazon rainforest tipping point

I have witnessed the effects of the Amazon rainforest tipping point myself. The prolonged dry season back in 2007 caused a water level in the flooded forests five meters below normal. Changes in the precipitation patterns also causes sudden droughts, confusing the natural ecosystems established over hundreds of centuries.

The indigenous people of Manaus, in the heart of the Amazon, were deeply worried about climate change. Rightly so, as increased temperatures causes changed precipitation patterns, withdrawing glaciers in the Andes mountains and unpredictable water levels in the Amazon river. Check out the first two minutes of this video for some more info!

Passing over to research scientist Schalk Cloete:

"The Amazon contains about half of the entire planet's biodiversity, produces about a fifth of the world's oxygen and contains about a fifth of the planet's fresh water. Quite an impressive repertoire…

Unfortunately though, the Amazon is already threatened by climate change. Two recent droughts, one in 2005 and another in 2010, have killed almost 4 million km2 of trees, releasing in the order of 10 billion tons of CO2 – a third of the annual human contribution.

The ecosystems within the Amazon are tightly interconnected, meaning that, if one or two crucial constituents fail, the entire system unravels. As a result, it takes only a 3 degree rise in temperature to wipe out the greatest biodiversity treasure on earth, releasing 10 years' worth of human carbon emissions."

lørdag 18. februar 2012

Climate change post 5: tipping points

Again, thanks to Schalk Cloete for contributing with the climate change posts! Here is number 5:

What really scares me is the sheer number of these things. Here are just a few: Melting polar ice increasing heat absorption, collapse of the Amazon rainforest causing massive CO2 emissions, thawing of Siberian permafrost releasing megatons of methane, deep-sea methane hydrates exploding to the surface, and anoxic oceans releasing further (poisonous and flammable) greenhouse gasses.

Each of these tipping points kick in at a different level of temperature rise and it is theorized that, once we cross enough of these tipping points, it will set off a self-strengthening cascade into oblivion. For example, the total collapse of the Amazon is projected at 3 degrees, which will push us over the Siberian permafrost tipping point, which will push us over the methane hydrate tipping point, which is projected to cause nothing short of a global cataclysm.

Enjoy the attached video of reasons to avoid all of this. The video also contains a very apt description of Homo sapiens: "A species fast in developing, but slow in maturing."

We really need to grow up…

tirsdag 7. februar 2012

Climate change post 4: Positive feedback loops.

A positive feedback loop is a self-strengthening spiral where a something is both a cause and an effect. Technology is a good example of a positive feedback loop. The more technology we have, the easier it becomes to come up with new technology. This and other "positive" positive feedback loops like knowledge, information and wealth have made our world very interesting, but could also lead to a disastrous positive feedback loop involving greenhouse gasses.

The planet is currently re-absorbing about a third of the CO2 we put into the atmosphere. The problem is that, once we cross a 2-3 degrees threshold, the planet's ability to absorb CO2 starts declining and eventually reverses, thereby joining us in pouring tons of greenhouse gasses into the atmosphere.

This threshold is called a "tipping point" as described in the attached video. (For those who don't understand German, clicking the "CC" button at the bottom of the video helps a bit.)

For more info on the science behind climate tipping points, get hold of "With speed and violence" by Fred Pearce.

Climate change post 3: Why the fuss?

When some confused old guy with a long beard stands on the street corner shouting, "The end is neigh!" most of us would just walk away with a bemused chuckle. However, when the world's leading climate scientists start writing this in peer-reviewed journals, it might just be time to start taking notice.

There is a general consensus that 6 degrees of warming constitutes a mass extinction event, wiping out 90% or more of all life. Yes, I know, this sounds totally crazy and farfetched, but the scientists have spoken (in their boring and objective kind of way).

Luckily 6 degrees is still far away (we are at 0.6 degrees now), but the problem is that once we cross a 2-3 degrees threshold, the planet itself might start marching unstoppably towards 6 degrees and beyond…

Get a copy of "Six degrees" by Mark Lynas – a highly readable, yet soundly scientific, global wake-up call.

Climate change post 2: The predictions.

Most studies predict a rise between 2 and 6 degrees by 2100, having impacts ranging from severe to catastrophic. One such model study is reported in the attached video. It may look a bit boring at first, but please put it on HD, notice the scale at the bottom and really focus on what happens to the planet with and without CO2 emission reductions.

This particular model shows a lot of warming especially on the poles and on the continents in general. How would you like to live in an Africa 8 degrees hotter than it is today? What do you think will happen to the ice at the poles with a full 16 degrees temperature rise? Scary thoughts…

At this stage, we all still hope that these models are overly pessimistic and perhaps over-estimate the greenhouse effect. But in any case, we cannot say that we have not been warned…

lørdag 4. februar 2012

Climate change post 1: Proof of anthropogenic climate change.

My dear friend Schalk Cloete has made an excellent series of climate change posts on Facebook. With the thoroughness of a true researcher he shows wise considerations about our current climatic situation, and with his permission I will share his posts with you:

"Here goes: The world emits 30 billion tonnes of CO2 yearly, amounting to about 15300 km3 in volume. At roughly 10 km thickness, the atmospheric volume is 5.11 billion km3. Dividing these two numbers reveals that humans raise the CO2 concentration by roughly 2.99 ppm yearly. Actual measured CO2 rises are around 2 ppm yearly, implying that the earth manages to absorb about a third of our emissions.

CO2 is a greenhouse gas. This means that it allows short wavelength solar radiation in, but captures and randomly redistributes long wavelength infrared radiation re-emitted by the earth's surface. Naturally, the heat captured increases with the CO2 concentration, hence global temperatures increase with CO2 concentrations.

97% of all peer-reviewed scientific literature agrees."

Whoa. How about we stop discussing whether or not global warming is manmade or not, but stick to the scientific research and start acting like we care?