Below is a summary of their presentation. Some of the information was taken from the work of Wally Broecker. Dr. Winter started off the presentation by explaining some figures and graphs related to historical climate variability, fossil fuel coupled sea level rise models, and where we should be in relation to our relationship with the environment (we are not where we should be). Before he handed over the rest of the presentation to his student, Juan Estrella, he explained the consequences of global warming and climate change. He mentioned that there are many repercussions of global warming; sea level rise, increase in the frequency and intensity of storms, increased global mean temperature, arctic shrinkage, arctic methane release, increased evaporation, erosion, changes in precipitation patterns resulting in floods and droughts, changes in circulation patterns of marine currents, spread of disease, increased probability and intensity of droughts and heat waves, economic consequences, global ecosystem out of balance, virus and wars.
Juan Estrella started off his portion of the presentation by leading into a discussion of different scenarios that we are facing. He mentioned that there are different scenarios that you can base the global warming situation off of. The first was coined by the presenters as the ‘business as usual’ scenario in which we continue to burn fossil fuels as we always have (+ 2 ppm/yr). The assumption under this scenario is that energy use will double by 2050 as the global population rises. This will elevate the CO2 concentration (2 ppm yearly will lead to 550 ppm CO2 by 2050 (present concentration = 390 ppm) in the atmosphere. The second scenario presented was the ‘prudent-cap’ where there is an eventual global halt in CO2 input into the atmosphere. They predicted that if the stop was initiated by countries and societies around the world we would still reach 560 ppm before everyone was able to completely become fossil fuel independent. They went on to say that it would take at least 50 years to completely implement a scheme, after it was initiated (~2035), to rid our dependence of fossil fuels. This would be by roughly 2085.
Why is CO2 the culprit for global warming? As sunlight enters the Earths atmosphere as short-wave hi energy radiation it is reflected and re-absorbed as long-wave radiation by CO2 and other greenhouse gases (water vapor, methane, aerosols, etc.) This long-wave radiation is trapped in the atmosphere by these greenhouse gases causing the ‘greenhouse effect’ which increases the global temperature. According to all climatogical models, planet temperature rises when CO2 is added to the atmosphere. In essence, the greenhouse effect is a positive feedback
loop where the addition of more CO2 will trap in more long-wave radiation increasing the lower atmospheric temperature leading to an increase in evaporation. Higher evaporation rates produces more gas (water vapor) which traps in more radiation and the cycle repeats itself with the addition of more CO2 into the atmosphere. As a result, the aforementioned consequences arise (i.e. land-based ice melting, sea-level rise, global temperature increase).According to the presenters the ‘naysayers,’ people in denial of global warming, claim that the warming in the last 30 years was because of the sun (with no supporting data), that warming in the early and late 20th century had no known man-made cause (which is true, but our planets climate has changed on its own as much as we have with greenhouse gases), and that the climate is no warmer than it has been in the last 12,000 yrs (which is also true, but the models predict that if we continue with ‘business as usual’ the temperature will rise far more). With those arguments presented, it is more clear why the majority of the world’s scientists agree that increases in CO2 is inducing an accelerated global climate change.
In order to relieve the environment from these global warming affects, the presenters listed a ‘road map for carbon management.’ They mentioned that we need a world-wide consensus mandating the reduction of the use of CO2, but also to diversify our use of alternate sources. Types of alternate sources that could be used by the world are hydrogen, solar, biomass, hydropower, wind, and nuclear. Some of these are more promising the others. For instance, hydrogen needs manufacturing and it also presents a storage problem so is not collectively thought to be the best option. Biomass production uses as much fossil fuels as it replaces and it presents the problem of fuel versus food. Solar is currently too expensive, but the technology is steadily moving forward so the future in solar may be promising. Wind is largely a local source and not a regional/global source, while nuclear energy looks the most probable for a clean alternative. But, nuclear power presents two problems, waste and probable terrorists attack. While the conservation of CO2 addition and alternate sources of energy are prescisely the way we should be moving we also need to enhance our ability to capture and store the CO2 in the atmosphere. According to the presenters, there was a method developed by Klaus Lackner to capture CO2 molecules and makes them into a liquid. They added that there is a wide range of storage sites being proposed (including deep aquiders, deep ocean, Antarctic lakes, etc.). In the end, the presenters mentioned that we need a ‘leveling of the playing field’ where there is an international agreement to clean the atmosphere by conserving, using alternates, and CO2 capture and storage methodologies.
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