Wood Romances

Paleoclimate studies offer some very useful information to help scientists understand where our climate is headed given our current concentrations of greenhouse gases. As I have shared in previous posts, the earth has warmed by 1.2°C above the 1850-1900 mean, with about 2°C total warming built into current CO2 levels, given an energy imbalance exceeding 0.8 W/m^2 and ECS of ~3°C for doubling CO2. However, this only considers rapid feedbacks operating on time scales of decades or so. Long term, over time scales of thousands of years, the Earth's climate system is sensitive enough to these forcings to cause drastic changes to the climate system. Earth System Sensitivity (ESS) is frequently estimated to be about 1.5xECS, so 2°C warming on time scales of decades will be amplified to 3°C warming on time scales of thousands of years.  The difference between the last glacial maximum (LGM) and the Holocene Thermal Maximum (HTM) is only ~4-6°C, but that difference in global average temperat...

Sea Level Rise Since 1900 Humans have been very concerned with sea levels for centuries, since understanding tides and sea levels has been important for maritime travel, fishing, and many other aspects of coastal living, including recreation. We have built tide gauges to monitor sea levels, giving us a long-term record of sea levels along our coasts that can now be used for measuring sea level rise (SLR) in response to climate change. As scientists have become more interested in paleo climates, they have also developed reliable means of estimating sea levels going back thousands of years. Both of these methods, proxies and tide gauges, are generally limited to estimating sea levels along our coastlines, but in early 1990s, scientists developed a means to use satellites to estimate sea levels, and this approach for the first time allowed scientists to estimate global mean sea level (GMSL) from most of the surface of the oceans, rather than just our coastlines. Each of these lines of evi...