E&ES 359Climate Change and the role of CO₂

Johan C. Varekamp

Climate change is common to this earth Ü we have known ice ages and hyper thermals, snowball earth and who knows what is in store for us for the rest of this century. In this class we will study the way in which the climate machine works, some effort will be made to study paleo climate indicators, and we will put a large effort in studying the current period of global climate change that may be human-activity driven.The role of CO₂ in earth processes is very large relative to the modest quantities of it that are present in the atmosphere. We will therefore study many aspects of the physics, chemistry and biology of CO₂ and carry out several projects that relate to CO₂. In addition, we will look into the role

of methane as a modifier of climate and catastrophic methane releases as a feedback to incipient warming. Several questions regarding CO₂ will be addressed:

• Is CO₂ cycling the ñthermostat of the earthî?
• What is the role of CO₂ in global climate (greenhouse gas)?
• How does photosynthesis works?
• How does CO₂ acidify surface waters and promote weathering?
• How much CO₂ is there on other planets?
• How has atmospheric CO₂ varied over the course of earth history?
• What should we do to prevent further global warming - the Kyoto treaty

The class will be split up in four groups that will run the various class projects:

• Atmospheric CO₂ monitoring
• Greenhouse experiments: the role of photosynthesis in regulating atmospheric CO₂
• Carbon cycle modeling
• Partitioning of CO₂ between water and air

The E&ES CO₂ monitoring site will begin collecting atmospheric data when the course starts. We will compare the Wesleyan CO₂ record with those from elsewhere and interpret variations in measured CO₂ contents at different time scales (day/night; weekly, seasonal, long-term) in terms of local and regional fluxes of CO₂. We will extract CO₂ databases from the WEB and re-plot them with our data, calculate fluxes of absolute amounts from data series, and other computer exercises. The work groups will create scenarios of global warming for emission densities of CO₂ in the world, and write essays or give presentations on scientific and political aspects. Professor Gary Yohe will teach a short module on the Kyoto treaty and regional adaptation models for climate change.

September

4Introduction to climate. Planetary comparison-why is Venus so hot, what happened at Mars, and what about the Earth?Ch. 1 + readings

9The modern earth climate: principles- Ch.2

11The greenhouse effect Ü principles Ü Ch. 2

16Convective climate and weather - Ch.2

18Climate archives and proxies Ü Ch. 3

23CO₂ and long term climate change Ü Ch. 4

25Tectonic forcing of climate Ü Ch.5.

30Long term climate history Ü Snowball Earth - Ellen Thomas

October

7The long carbon cycle revisited

9The short term cycle of C

16Carbonate chemistry in the oceans

21Biological processes, photosynthesis

23¹⁴C as a tool in climate studies

28Other carbon forms and their cycles (methane, CO)

30Volcanoes and climate

November

4Historical changes in climate Ü Ch.16

6  Modern and historic anthropogenic carbon releases

11Reducing the anthropogenic carbon releases Ü Kyoto treaty - Yohe

13Climate change and society Ü Mitigation or adaptation? - Yohe

18CO₂ disposal approaches

20Future climate: models, effects

25Project presentation

December

4Project presentation

9away