This is the most recent in a series of guest posts by leading climate scientists, science writers, policy makers and others involved in the ongoing debate about climate policy. We’ll be hearing from these guests regularly leading up to COP15 in December.

by Pedro Leon Azofeifa
Although climate change has only relatively recently become a hot-button political issue, the idea that changes in the composition of our atmosphere could have serious consequences is not a new one. Around the turn of the century, Svante Arrhenius, the Swedish Nobel prize winner in physics, was the first scientist to become concerned about green-house gases (GHG). Standing on the shoulders of the great French scientist Jean-Batiste Fourier, who observed that some gases absorb more heat energy than others, Arrhenius estimated the increase in air temperature if atmospheric carbon dioxide (CO2) were to double in concentration. He concluded that such doubling of CO2 would raise air temperatures by 9°F (5°C). Alarmed by the carbon that was unleashed by the internal combustion engine and the industrial revolution, he stated, “We are evaporating our carbon mines into the air.”
The industrial revolution transformed the way we use energy: humans, who for most of history depended on energy produced by current photosynthesis, were now living on energy produced by ancient photosynthesis: carbon, oil, and gas. The vast deposits of carbon created by ancient photosynthesis were transferred back into the atmosphere during the industrial revolution, to the tune of many gigatons (10¹²) of carbon every year. The outstanding issue is that we have removed gigatons of solid carbon, the result of years of photosynthesis, and converted it into carbon gases by burning fossil fuels, by cutting down our forests, and by emitting methane (another potent GHG, identified by Fourier) from our waste products.
Since Arrhenius time, it has become clear that the accumulation of anthropogenic (or derived from human activities) GHG is not a hypothetical problem, although over half a century went by before his concerns were resurrected. In 1957, the Scripps Oceanographic Institute hired a young scientist named Charles Keeling to establish monitoring stations in Hawaii and the Antarctic. For decades, Keeling accumulated daily records, detecting without a doubt a constant yearly increase in CO2 concentration, whose rate of increase was also increasing. Initially rates were measured at 0.7ppm (parts per million) per year, then later at 1.5 ppm/year, and currently at about 3.0 ppm/year, bringing us to a present day concentration of approximately 387ppm. If we continue with business-as-usual, then by 2050, the actual rate of increase could double the concentration of atmospheric CO2 from pre-industrial concentration, putting us at a concentration of around 560ppm. Remarkably, the advanced computer systems that are now used to analyze climate change have largely confirmed Arrhenius’ calculations.
The consequences of this increase in GHG have been analyzed by many scientists, including the consortium of the Intergovernmental Panel on Climate Change (or IPCC) of the United Nations. The IPCC predicts many catastrophic effects driven by the impact of GHG on climate patterns, ice melting, ocean life, and atmospheric transformations. These scientists have also come to understand that the climate system is very complex and subject to many inertial and feedback effects that may not always be predictable and will require continuous refinements of the climate models. At any rate, many experts propose that climate change impacts are already evident and will increasingly represent a hazard and cost to nations at risk. The effects will not be limited to changes in weather–the economic impact of climate change has been addressed by Nicolas Stern, who concluded that rapid action to address climate change now will represent immense savings.
The COP15 meeting in Copenhagen is indeed of great importance to the future of high risk territories like islands and low lying shores. The Central American Isthmus (which includes Costa Rica) is one of those high risk regions due to its proximity to the unstable Caribbean basin and the Pacific Ocean, with a newly found potential for generating storms and hurricanes. It is also a highly seismic region with much volcanic activity. It is clear that regions like ours will require mitigation and adaptation activities. Lowland regions will have to be monitored and readiness plans should be prepared and communicated.
Costa Rica has participated actively in the meetings preparing for the Copenhagen event. Carolina Mauri, an environmental lawyer, has represented the Presidential initiative, working closely with the Ministry of the Environment (MINAET) and the Ministry of Foreign Relations. During the launch of the Peace with Nature Initiative, President Oscar Arias proposed that Costa Rica become carbon-neutral by the bicentennial of independence in 2021, making ours one of the first countries to mitigate for all its anthropogenic emissions. This is a position that is simple to understand and which can, in principle, be adopted by individuals, companies, universities, cities, regions, and whole countries. Several other countries have made similar commitments to complete mitigation before the end of the century.
Of course, the success of Costa Rica in reaching this goal, which principally involves changes in its transport system, will make very little difference if all countries do not make similar commitments. The target baseline reached after human economies become de-carbonized will presumably be about 350ppm. Success in meeting this target will indeed require funding, research, innovation, and sharing of new technologies that can harness solar, wind, water, and geothermal sources. More information at www.pazconlanaturaleza.org.
Pedro Leon Azofeifa, Scientific Advisor to the President of Costa Rica – Dr. Leon, a founding member of the Costa Rica Academy of Sciences and the first Costa Rican scientist to be elected to the United States’ National Academy of Sciences.


