The Two Cs…

So far, all my blog posts have been all about my life in Quebec and my PhD on chaetognaths…

However, the major reason I’m doing Arctic science, is to try and understand how the Arctic works, with the ultimate aim of protecting it. One of the things that it needs protected from the most is a monster called “current climate change”. Below is a brief overview of the problems of climate change in the 21st century, in my eyes. This is just an introduction to the subject, but I hope it will open the door for future discussions on this via my blog. Take care jx

Humans are developing rapidly. In the last 300 years, the global population rose tenfold to over 6 billion. It is expected to reach over 10 billion by the end of the century. The Anthropocene commenced in the 18th century. At this point there was a step change in emissions of greenhouse gases (GHGs) e.g. carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) into Earth’s atmosphere (Crutzen 2002). CO2 is often described as the “most important” GHG, with highest emissions. Anthropogenic activity during the 20th century accounts for a 30% rise in CO2 levels (Crutzen 2002). Over the period 1970 to 2004, annual CO2 emissions rose by ~80% (IPCC 2007). The current atmospheric CO2 level of 385ppm exceeds that of any time in at least the last 400,000 years (Crutzen 2002).

CO2 plays a key role in modifying climate, by trapping infrared radiation above the Earth’s surface. Increasing atmospheric [CO2] enhances the greenhouse effect and warms the planet (IPCC 2007). As a result the eleven years 1995-2006 were some of the warmest years since 1850 (IPCC 2007).

Gas emissions from industry are a big part of the problem…

Global warming has already caused changes in characteristics of sea and land ice, flora and fauna, humans, ocean circulation and weather (e.g. Walther et al. 2002, ACIA 2004, IPCC 2007). The “second problem of CO2“, as it has come to be known, is ocean acidification. COreacts with seawater to form carbonic acid which dissociates into carbonate, bicarbonate and hydrogen ions. The carbonate ions are needed by many marine creatures to build shells for protection. Examples of animals which do this are corals and beautiful zooplankton called pteropods. But the more Hydrogen ions there are in their environment, the harder it is for these animals to take much-needed carbonate ions into their shells and skeletons. Absorption of CO2 by seawater has already reduced its average pH, the measure of acidity (lower pH means more acidic), by 0.1 below its pre-industrial value (Bengtsson 2006). That low number might not sound like much, but it translates into a lot more Hydrogen ions, and this has already made life harder for many a marine critter. Ocean acidification is a problem which won’t go away any time soon!

If current emission trends are allowed to continue, CO2 levels at the end of this century could be 3 times higher than pre-industrial levels, which could lead to a mean surface temperature rise of 7oC (Allison et al. 2009). However a rise of just 2-3oC to 450ppm could possibly be “dangerous” (Hansen et al. 2009). And levels above 1000ppm could cause cataclysmic and irreversible consequences, including severe deterioration of the Greenland Ice Sheet and consequent sea level rise that “will displace more than a quarter of the population of the world” (Schnare 2007).

Future climate change is a major threat to mankind (Hansen et al. 2009). At the Rio Earth Summit in 1992, the UN Framework Convention on Climate Change “committed the nations of the world to avoid dangerous anthropogenic interference with the climate system” (Schneider 2001).

The most logical solution to the problem is to abate further emissions but this is proving easier said than done. Workers at the Centre Center for International Climate and Environmental Research in Oslo suggest that a global reduction target of 80% is necessary to prevent 2oC warming (Carlin 2007). That’s a big percentage and seems an unrealistic target because the trend in current global emissions is not even heading in the right direction; emissions are actually growing at a rate of 1% yr-1 (Parliamentary Office of Science and Technology 2009). A major explanation is that significant reduction efforts are only being made by a few nations. Many undeveloped nations have not shared the same enthusiasm to abate emissions (Carlin 2007).

Mitigation does not seem to be working fast enough and could be unable to beat the climate change problem alone. Now may be the time to explore high tech methods of reducing the concentrations of COalready in the atmosphere…

[To be continued]

References

ACIA, 2004. Arctic Climate Impact Assessment. New York: Cambridge University Press.

Allison, I. et al., 2009. The Copenhagen Diagnosis. Up­dating the world on the Latest Climate Science. Sydney: The University of New South Wales Climate Change Research Centre (CCRC).

Bengtsson, L., 2006. Geo-engineering to confine climate change: is it all feasible? Climatic Change, 77, 229–234.

Carlin, A., 2007. Risky Gamble. Environmental Forum, 24(5), 42-47.

Crutzen, P., 2002. Geology of mankind. Nature, 415, 23.

Hansen, J. E. et al., 2009. Target atmospheric CO2: Where should humanity aim? Open Atmospheric Science Journal2, 217–231.

IPCC, 2007. Climate Change 2007: Synthesis Report. Geneva: IPCC.

Parliamentary Office of Science and Technology, 2009. Geo-engineering research. Postnote, 327, 1-4.

Schnare, D. W., 2007. A Framework to Prevent the Catastrophic Effects of Global Warming using Solar Radiation Management (Geo-Engineering). Supplement to testimony before the United States Senate Committee on Environment and Public Works, Washington, D.C., October 3, 2007. Available from: thehardlook.typepad.com/…/schnare_supplemental_testimony_a_framework_for_geoengineering.pdf

Schneider, S.H., 2001. Earth systems engineering and management. Nature, 409, 417–421.

Walther, G.R. et al., 2002. Ecological responses to recent climate change. Nature, 416, 389–395.

 

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