My research is focused on the rapidly changing Arctic: why it's happening, how changes are affecting the Arctic system, and how disproportionate warming there is affecting temperate regions on Earth, where billions of people live.

My early papers address the Arctic itself. I used new information derived from satellite data to better understand how energy and moisture flow between the atmosphere, surface, and regions south of the Arctic. This work led to studies of the various causes of sea-ice variability and loss -- such as changes in clouds, water vapor, energy transport, and winds -- which ultimately are responding to increasing greenhouse gases owing primarily to burning of fossil fuels.

Recently I have been researching connections between rapid Arctic warming (aka Arctic amplification, AA) and weather patterns in mid-latitudes. We hypothesize that AA will lead to more persistent weather regimes, such as the recent multi-year drought in California followed in 2016/17 by record-breaking precipitation, illustrated in the photos to the right. These Arctic/mid-latitude connections are complicated and difficult to pin down convincingly, however, and I am pleased to be collaborating with an ever-growing number of excellent colleagues to investigate this exciting and important aspect of our changing climate.

I have also devoted more of my time in recent years to becoming a more effective science communicator. I want to help non-scientists gain a deeper understanding of why the climate is changing and how it already is and will continue to affect each and every one of us in profound ways.

Winter 2014/15

in the Sierra Nevada

Winter 2016/17

in the Sierra Nevada