“Are forests good for water?” remains a hotly contested scientific question. Despite both its importance and apparent simplicity, we have difficulty knowing enough about how the water regime reacts to land use change to make water-wise decisions regarding the forest management alternatives facing individuals, communities and governments.
In the face of global warming and climate change, the preservation and extension of forest cover is likely to play an increasingly important role in the maintenance and improvement of available water supply. But given the complexity of the science, and the scale issues involved when contrasting local management vs. regional and global issues, it is difficult to know how to include water in forest management.
Using the situation in Ethiopia as a starting point, the relation between land cover and water over the past half century has been explored using both traditional methods (runoff records, statistical analysis, and change detection modeling), as well as an exploration of community perception.
The Pacific coast of South America experienced numerous dramatic climatic changes during the Cenozoic Era. Mollusks along this coastline provide one of the main exceptions from the latitudinal diversity gradient of decreasing species numbers toward the poles. From 42°S southward, coincident with the onset of the mosaic coastline of the southern Chilean fiordlands, species numbers show a twofold to threefold increase compared to the central Chilean coast. The Neogene and Quaternary fossil record (= since ca. 23 million years ago) of central and southern Chile was used to test hypotheses on the origin of this unusual pattern. Contrary to previous suggestions, no evidence was found for an accumulation of biodiversity since the Eocene, or for the northward spread of Antarctic taxa into southern mid-latitudes. Rather, the data suggest that the mosaic coastline south of 42°S was colonized after the retreat of the glaciers from their marine termini since the later Pleistocene, by taxa that were already present along the Chilean coast.
Terrestrial ecosystems are part of the climate system. Climate-induced changes in vegetation composition, structure, distribution and greenhouse gas exchange feed back to the atmosphere from local to global scales. Current regional and global climate models account for instantaneous biophysical responses of land surface energy and water vapour exchange with the atmosphere. Emerging Earth system models also represent longer-term responses mediated by physiological processes and ecological interactions, but issues remain. Illustrating with simulation results from offline and coupled biosphere-atmosphere simulations with LPJ-GUESS, a second-generation global vegetation-biogeochemistry model, I highlight examples of how ecology – i.e. responses of organisms to a changing physical and biotic environment – influence forcing factors of relevance to climate dynamics globally and within the contrasting bioclimatic contexts of the Arctic and tropics.
Panel discussion with Thomas Cronin (US Geological Survey, Susanna Baltscheffsky (SR Klotet), John Gustavsson (Väsby Gymnasium), Andres Jato (Arctic Council) and Nina Kirchner (Bolin Centre for Climate Research).
How can something as remote as the Arctic play a globally important role? How can scientist share their knowledge of climate in an accessible way?