Palynological data as tools for interpreting past climates: Some examples from Northern North America

Documenting past climates and their associated terrestrial ecosystems is one means of predicting how modern landscapes may respond to changing atmospheric composition resulting from the addition of greenhouse gases. Fossil pollen preserved in lake and bog sediments is an especially valuable source of paleoclimatic information. Initially, pollen records were used only as qualitative estimates of climate change, but more recent analyses indicate they can provide accurate quantitative reconstructions. The floristic simplicity of tundra and boreal forest and the coarse taxonomic resolution of northern pollen taxa were believed to seriously limit the use of pollen for interpreting high latitude paleoclimates. However, current studies in Alaska and Canada demonstrate that pollen data are relatively strong and sensitive climate indicators. The status of paleoclimate reconstructions based on pollen records from northern North America is discussed using isopoll maps, response surfaces, analogs, and percentage diagrams