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Significance of Our Article

  • Warming rates are not very informative
    • Most people cannot immediately understand the consequences between a warming rate of 0.2oC/decade vs. 0.3oC/decade.
    • The impacts of warming are connected to how temperature changes through out the year. For example, if the winters warm and the summers do not, or if the summers warm and winters do not, the impacts can be very different.
  • Seasonality is the rhythm of life in the North
    • Seasons become more distinct as you go North. In the winter, sunlight is weaker, day length is shorter and the air and land are cold. In the summer, it is the opposite.
    • The short summers in the North provide a sudden supply of abundant food to birds and animals. Hence, the annual migration to the North. The other seasons are inhospitable - they escape South. Some animals hibernate. More info.
    • A change in Sun-Earth geometry can change seasonality. And, it does, over a period of 20+ thousand years. However, it is also possible to quickly (100 to 200 years) warm the colder periods of this seasonal rhythm with the amplified greenhouse effect.
  • Temperature seasonality is decreasing in the North
    • The highly-seasonal Northern lands are beginning to resemble their less-seasonal Southern neighbors possibly because of the amplified greenhouse effect.
    • All state-of-the-art computer models of climate are predicting a large decrease in temperature seasonality in the North by the end of the 21st century - actual observations from the past 30 years agree with model predictions thus far.
  • Vegetation seasonality is decreasing in the North
    • Heat controls plant growth in the North. Warmer springs create longer growing seasons because there is ample sunlight. The plants are thriving. The landscape is beginning to look like its lusher and less-seasonal Southern counterparts - that is, vegetation seasonality is also decreasing.
    • However, the benefit of extra heat is decreasing in some areas because there is not enough rainfall to sustain the greener landscape. This is increasing the risk of fires and pest attacks.
    • We observe all of this in the past 30 years of satellite data.
  • Uncertain Future
    • We do not know what the future holds for Northern lands as this depends on the magnitude of the amplified greenhouse effect.
    • Done to an extreme, this can have disastrous consequences (e.g. rising sea levels, ice-free Arctic ocean, little snow on land, thawing and slushy grounds, outgassing of more greenhouse gases, etc.).
    • In short, the rhythm of life not only in the North, but all that is connected to it (for example, migration), can be turned in to noise.
Climate and Vegetation Research Group
Dept. of Geography,Boston University. XXX-XX-2013