“Climate is what you expect,
weather is what you get.”
Warming Temperatures: Vermont’s temperatures are projected to rise by another 2-3.6° F by 2050 and 5-5.4° F of warming by 2100 according to computer simulation models by the IPCC based on low to high global emissions of greenhouse gases (IPCC– Christensen et al. 2013).
Increasing Precipitation: Precipitation will continue to increase over the next century in Vermont, with the largest increases occurring in mountainous regions. In the near-term over the next 25 years, much of this precipitation will fall as snow in the winter. As temperatures continue to increase winter precipitation will shift to rainfall in the next 50 years and beyond.
Weather Extremes: The chances of record-breaking high temperature extremes will continue to increase. High nighttime temperatures are increasingly common. Warmer nighttime temperatures threaten snow and ice cover for winter recreation and will cause increased demand for cooling in winter and summer, respectively. An increase in high-energy lightning storms is projected to continue, threatening infrastructure and transportation systems.
The Jet Stream: Vermont’s short-term weather is delivered by the jet stream that moves from season to season. Recent “blocking” or quasi-stationary patterns in the jet stream have led to prolonged periods of intense rainfall (e.g., June 2013), dryspells (e.g., August 2012), or intense cold (e.g., Polar Vortex 2014). Blocking patterns will be more common as they are due to loss of Artic Sea ice and will bring Vermont unseasonably high or low temperatures and/or precipitation.
The Vermont Climate Assessment was created by a unique team at the Gund Institute for Ecological Economics at the University of Vermont. Led as a graduate course consisting of students with expertise in forestry, water resources, agriculture and farming, economy, community development and planning, energy and climate change science. Lead authors of each chapter garnered support from partners including the National Weather Service, state agencies, climate experts, and Vermont farms and businesses. All lead authors consulted, co-authored, or were reviewed with/by external experts in the subject matter. The leads collected data and subject matter from literature, interviews and observational data.
Why the VCA
The Vermont Climate Assessment seeks to address three main goals focused on the state of Vermont: 1) further scientific understanding of global change trends using local, historical data; 2) develop a deeper understanding of future impacts of climate change using simulations of future climate, and 3) communicate the current state of knowledge on global change impacts on Vermont, focusing on agricultural production, forests, water resources and recreation industries.
GRAPH TO COME
Rising Temperatures: Average annual temperature in Vermont has increased by 1.3° F since 1960; 45% of this change is since 1990. Winters are warming twice as fast as summers. Warmer temperatures have caused later “first-fall freeze” and earlier “last-spring freeze”. Over the past 40 years, the freezing period has shortened by 4 days each 10 years and the growing season has lengthened by 3.7 days every 10 years.
GRAPH TO COME
Increasing Precipitation: Precipitation has and will continue to increase, particularly in winter months. Since 1960, average annual precipitation has increased 5.9 inches; almost half (48%) of this change in rainfall has
occurred since 1990. The greatest increases are in the mountainous regions. Heavy rainfall events are becoming more common, posing threats to development in floodplains and to water quality as the historical legacy of fertilizer use in agricultural areas supplies high levels of nutrient run-off into rivers and lakes.