Question 1 [8 points]

The Earth System Research Laboratory of NOAA, a branch of the U.S. government, measures atmospheric greenhouse gas concentrations from stations and aircraft around the world. The famous graph of atmospheric CO₂ concentration from atop Mauna Loa in Hawaii (reported in ppm or parts per million), as well as data on annual growth rate (ppm/year), can be found on the NOAA web-site:

Graph back to 1958: http://www.esrl.noaa.gov/gmd/ccgg/trends/full.html

a) What is the annual mean atmospheric CO₂ concentration at Mauna Loa for 2010? [1]

b) Using the value from (a), by what percent has the atmospheric CO₂ concentration increased from the pre-industrial value of 280 ppm. [1]

% increase of CO2 concentration = (Year 2 CO₂ ppm  – Year1 CO₂ ppm) / (Year 1 CO₂ ppm)  

c) Using the annual mean growth rate data available on this link http://www.esrl.noaa.gov/gmd/ccgg/trends/gr.html, calculate the mean or average annual growth rate in ppm/year for the 1960s (1960-1969) and the 2000s (2000-2009).  [2]

d) By what percent did the growth rate change from the 1960-1969 period and the 2000-2009 period? (e.g. 4% increase) [1]

e) Based on the carbon budget discussion in the climate change class, list three carbon flows (inputs) that could explain the change in the growth rate [3]

Question 2 [7 points]

After studying climate observations and the results of global climate models, a group of scientists determined that carbon dioxide-driven global mean temperature change (ΔT) can be roughly estimated directly from cumulative carbon emissions (CE). The calculation uses what they call the “carbon–climate response”, which is equal to ΔT/CE. Their data suggested that the “carbon–climate response” is roughly 0.0015 °C per billion metric tonnes of carbon emitted.

a) Over the past five years, global annual carbon emissions from fossil fuel burning averaged 9 billion metric tonnes of carbon per year. How warming would eventually result from one year of carbon emissions at this rate? [2]

b) The total global carbon emissions from fossil fuel burning since the Industrial Revolution are roughly 383 billion metric tonnes of carbon. How much warming should that generate? [2]

c) What percent of warming should come from carbon emissions within Canada, which is responsible for 7.4 billion metric tonnes of carbon since the Industrial Revolution? [1]

d) the median answer provided in (b) is less than the warming observed to date? Why do you think that is the case? Provide a brief explanation [2]