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Climate Change

Everett Lasher in Greenland

Daniel Horton's Climate Change Research Group (CCRG) studies the Earth’s atmosphere and its interaction with human and natural systems. Industrialized society is currently engaged in a real-time sensitivity experiment with planet Earth. While the steady addition of greenhouse gases to the Earth’s atmosphere is known to warm the planet, climate system feedbacks and downstream impacts remain uncertain. Working with both observed and model-simulated data, the CCRG investigates a range of topics designed to enable societies to make informed decisions about their future. Research foci include: extreme weather events, hydrological change, near-term meteorological, societal, and public health impacts, and sustainable design solutions for urban environments. To address this diversity of topics, a wide-range of research tools are employed – environmental observations, numerical models, statistical analyses, and machine learning techniques. 

Yarrow Axford's research group examines past and present-day climate change in the Arctic and beyond, including Northwestern’s backyard in the Midwestern U.S. Diverse analyses of lake sediments and other geologic records can provide answers to questions like: What are recent temperature trends in remote regions, and how do recent decades compare with past centuries and millennia? How (and how rapidly) do ice sheets and smaller glaciers respond to warming, and what does that imply about future sea level rise? Are mountain glaciers in remote, relatively unstudied areas on a path towards disappearing soon? Did the Norse (Vikings) really benefit from a warm climate when they settled in Greenland during Medieval times?  What do Arctic ecosystems look like in warmer or colder climate regimes? Much of the work in Axford's Quaternary Sediment Lab focuses on the late Quaternary, with special emphasis on methods for developing precise Holocene paleoenvironmental records that extend to present day.

Andrew Jacobson: Over geological timescales (millions of years), the chemical weathering of silicate rocks controls atmospheric CO2 levels and regulates global temperatures via the greenhouse effect. Quantifying this mechanism and its primary controls is critical for understanding how Earth became and remains habitable. To understand the long-term carbon cycle, members of the Jacobson group study the elemental and isotope geochemistry of rivers draining diverse tectonic, lithologic, and climatic settings. Current field areas include Iceland and the New Zealand Southern Alps. Jacobson and his students also study the rock record to detect climate change and related phenomena, such as ocean acidification events, in deep time.

Neal Blair’s Carbon Biogeochemistry Lab investigates the relationship between the C-cycle and climate. Current research involves understanding how C-losses from landscapes and subsequent downstream C-sequestration may be impacted by future climate change. The lab is trying to determine whether agricultural soil C-losses are actually a net source of CO2 to the atmosphere or a net sink. Other studies have involved using the preserved sedimentary organic record in lakes and ocean sediments to reconstruct past climate change.