Climate Change: A planet in flux
A combo of history and primer, this is going to Good Reads as well.
How is life on Earth reacting to climate change?
Human activities have added billions of tonnes of carbon dioxide to Earth's atmosphere, causing global temperatures to rise. We are beginning to see how warmer temperatures are altering climates all over the planet and to understand the effects they are having on animals, agriculture and people. What will Earth look like in the year 2100? How will climate change have altered the planet's biology?
A changing world
Fly over the high Arctic in summer and you will see a landscape speckled with shallow ponds, some ringed by mossy wetlands. Frozen for most of the year, these ponds melt for a few months and become biodiversity hotspots teeming with plants, animals and microorganisms. The Arctic's isolation and extreme environment have made it difficult to gather observational data on the region's ecological changes, and existing records are sparse and incomplete. Fortunately, the ponds and lakes in this region can help scientists build a picture of the high Arctic's environmental conditions going back thousands of years.
The sediments of these remote ponds reveal their history. They contain pollen grains, dead algae and invertebrate fossils, as well as other biological, chemical and physical information. Their accumulation at the bottom of the ponds, one layer on top of the next, produces a vertically arranged historic timeline. Rather like tree rings, which reflect the growing conditions of years past, sediment records provide a glimpse of earlier climates and environmental disturbances. We can think of them as being like an aircraft's 'black box', only for the ecosystem.
In 1983, my lab began studying about 40 of these freshwater ponds on the east–central side of Ellesmere Island, the most northerly island in the Canadian archipelago. We chose shallow ponds because their small size means they are highly susceptible to change. Each year we return to the Arctic to collect water samples and sediment deposits from these ponds and other northern regions for comparison.
More: http://www.nature.com/nature/journal/v483/n7387_supp/full/483S12a.html
