Rapid Climate Change and Climate Surprises. A Look Back and Ahead

The concentration of carbon dioxide in the atmosphere today is 383 parts per million. This increase of 40% from the normal state has occurred over just the past 150 years. The increase in carbon dioxide concentration, a result of the combustion of carbon-bearing fuels like oil, coal, and gas, along with a change in landscape conditions resulting in deforestation and soil loss, has caused measurable changes in climate. The most important questions now facing scientists and policy makers are not related to whether climate change is occurring but rather the extent and rate of climate change and the consequent impacts on ecosystems, agriculture, and humans. Although the effects of global warming can be generalized to global averages in terms of temperature and precipitation, people and countries are not impacted significantly by global averages, but rather by regional and local effects where they live, grow food, and produce materials.

This presentation focuses on climate change from a number of perspectives, with the goal being to put into context the expected changes over the next 100 years and present several of the potential climatic surprises that we may also need to be prepared for. A particular cooling event that occurred about 8,200 years ago will be examined in some detail, as it provides a window into the profound global effects that can occur with only a subtle change in ocean circulation. Additionally, the intersections between humans and climate change will be examined from a social-collapse perspective, using the Mayan Civilization as an example of poor resource utilization and the importance of anticipating change and building infrastructure for flexible response. This presentation is meant to examine the potential impacts of climate change that directly affect people, cities, states and countries, providing some lessons from the past and windows into the future.