Wednesday, April 23, 2008

Have We Reached a Tipping Point?

The whole global climate change (GCC) issue has been riven with controversy (whether folks care to admit it or not) as to whether people have their facts straight, or are interpreting them correctly. Whether or not you believe that humanity is driving climate change, a change is occurring. What are we going to do as we start feeling the impact of that change? How will we prepare for it?

The North Pole is H2O. It freezes up and melts in a cyclical pattern consistent with the cycle of the Earth as it orbits the sun. However, the sea ice minimums are becoming even more minimal than has been the norm in recorded history, or at least history as recorded by Europeans and Americans. This is a serious matter becauses more water is exposed to summer sun, absorbs that energy, and freezes more slowly. And the evidence is now appearing (see April 7, 2008 entry) that not only are the minimums shrinking each year, the replacement ice that is appearing is 1st year ice, therefore thinner and easier to melt when summer arrives. The sun does not have to bore through multiple years of ice deposits to reach liquid water. This suggests to the researchers that we are looking at a much earlier onset of an ice-free North Pole in the summer. The consequences for planetary climatology are not clear to me, but there will be consequences, including the impact on polar creatures whose environment will be disrupted.

One possible effect is being noticed in Siberia. The researchers clearly don't know what is going to happen in the short-term, let alone the long-term, but the fact that the seabed has warmed up sufficiently to release methane is worrying. There is precedent for this, although not all are convinced.

Either way, the Siberian discovery speaks to the impact of a temperature rise that enabled the water to stay warmer longer. This may be the tip of the proverbial iceberg.

Now before anyone runs off to chat about the snow in Antarctica, let's do a little review:

The Antarctic is a continent, complete with mountains. It is covered in snow and ice, and has withstood the impact of global warming as felt at the Arctic for a good reason:

Antarctica is colder than the Arctic for two reasons. First, much of the continent is more than 3 kilometers (2 mi) above sea level, and temperature decreases with elevation. Second, the Arctic Ocean covers the north polar zone: the ocean's relative warmth is transferred through the icepack and prevents temperatures in the Arctic regions from reaching the extremes typical of the land surface of Antarctica.

OK - 2 good reasons.

However, the breakup of the Wilkins Ice Shelf this year (with the remainder clinging to the continent), comes 6 years after the Larsen B collapse. It opens a door for additional melt from the glaciers associated with the peninsula, the one area feeling the heat, as it were. The peninsula will be watched, even as the interior of the continent remains its usual chilly self.

So please, before you tell me that GCC is not happening, find me another reason for these events. Human activity on this world probably did not initiate the cycle leading us to this moment, but we would be foolish to assume that human activity is not amplifying the effects.

If we have reached a tipping point, or are near to it, our descendants may not think kindly of us if we haven't done something to prepare for or mitigate those effects. Assuming they have time to reflect on the past while managing their own survival.

2 comments:

Michael J. Harrington said...

The Siberian shelf article is really amazing. The line that stopped me cold was "...the permafrost bottom of the 200-meter-deep sea..." Permafrost? I never imagined that there was anything at the very bottom of an ocean but dumb, silent, and harmless rock.

The next line was powerful enough that I had to read it twice: "... enormous stores of gas hydrates lie dormant in mighty frozen layers of sediment. The carbon content of the ice-and-methane mixture here is estimated at 540 billion tons. "

Hundreds of billions of tons? The idea of it all makes several thoughts come at once. Surprise and awe are at the top of the list. I bet lots of scary-as-hell movies (sci-fi films about deep sea labs and explorers, corporate methane exploitation schemes gone horribly wrong, etc.) will be made about this long before we figure out how to handle the potential crisis.

Thanks for sharing this. I continue to learn from this blog.

Kheris said...

Methane hydrates (or their relatives) actually hold potential as a fuel source, but become unstable as their environment warms. There is plenty of evidence of releases from the ocean floor. One theory hypothesizes that explosive releases account for the mysterious ship disappearances in the Bermuda Triangle, not little gray aliens or some sci-fi inspired temporal-spatial anomaly. Japan is doing some work around harvesting this stuff because it is a gas that can work as a fuel for us. If they solve the technical, and technological, issues, it could offset the decline in other fossil fuels. It is quite a challenge.