Latest Score:

4.8/5

in 2019

score trend is flat over time
Weight: 10%

As our climate changes, it is predicted that there will be greater variability in annual temperatures, as well as warmer maximum temperatures in the summer. Higher summer temperatures can lead to drought and heat stress to forests, resulting in declines in tree health and tree mortality1,2,3. Here, we assess the change in maximum annual temperature in Vermont. Tree are adapted to the long-term conditions they have experienced, therefore deviations in maximum temperature from the long-term mean (both above and below) could be problematic to forests. A high score means that the maximum temperature is close to the long-term mean.

1Anderegg, W.R., Kane, J.M. and Anderegg, L.D., 2013. Consequences of widespread tree mortality triggered by drought and temperature stress. Nature Climate Change, 3(1), pp.30-36.
2Williams, A.P., Allen, C.D., Macalady, A.K., Griffin, D., Woodhouse, C.A., Meko, D.M., Swetnam, T.W., Rauscher, S.A., Seager, R., Grissino-Mayer, H.D. and Dean, J.S., 2013. Temperature as a potent driver of regional forest drought stress and tree mortality. Nature Climate Change, 3(3), pp.292-297.
3Rustad, L., Campbell, J., Dukes, J.S., Huntington, T., Lambert, K.F., Mohan, J. and Rodenhouse, N., 2012. Changing climate, changing forests: The impacts of climate change on forests of the northeastern United States and eastern Canada.

Maximum temperatures are increasing and expect to continue to increase. As winter temperatures warm, more insects can survive the cold season and have higher spring populations. Warmer winter temperatures also contribute to less snowfall and/or snowcover. Rising temperatures may lead to mortality of some tree species. Warmer temperatures also increase evaporation and dry soils, contributing to summer drought.

Additional Resources

National Climate Assessment 2014

National Climate Assessment 2018

NCEI State Summary for VT

Interpretation provided by:

NOAA, Northeast Regional Climate Center at Cornell University (2020)

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The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.

Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.

Component Description
Scored as

Distance away from long-term mean (scaled 1-5)

Target value

Long-term mean

Directionality of scores

No change from the long-term mean is better.

Minimum value used in scoring

Data minimum - 10% of range

Maximum value used in scoring

Data maximum + 10% of range

Data of mean maximum annual temperature for Vermont were gathered from NOAA National Centers for Environmental Information1. We set the target for the dataset as the mean maximum temperature from1961-1990 which is used as the baseline normal for climate comparisons by the Intergovernmental Panel on Climate Change (IPCC). The current year is scored for where it falls between the target and the upper scoring bounds (maximum value in the dataset) or the lower scoring bounds (minimum value in the dataset), scaled to be between 1 and 5.

1 NOAA National Centers for Environmental Information. 2019. Available at: https://www.ncdc.noaa.gov/cag/

STRESSORS INDICATORS