Boreal forests, aerosols and the impacts on clouds and climate.
نویسندگان
چکیده
Previous studies have concluded that boreal forests warm the climate because the cooling from storage of carbon in vegetation and soils is cancelled out by the warming due to the absorption of the Sun's heat by the dark forest canopy. However, these studies ignored the impacts of forests on atmospheric aerosol. We use a global atmospheric model to show that, through emission of organic vapours and the resulting condensational growth of newly formed particles, boreal forests double regional cloud condensation nuclei concentrations (from approx. 100 to approx. 200 cm(-3)). Using a simple radiative model, we estimate that the resulting change in cloud albedo causes a radiative forcing of between -1.8 and -6.7 W m(-2) of forest. This forcing may be sufficiently large to result in boreal forests having an overall cooling impact on climate. We propose that the combination of climate forcings related to boreal forests may result in an important global homeostasis. In cold climatic conditions, the snow-vegetation albedo effect dominates and boreal forests warm the climate, whereas in warmer climates they may emit sufficiently large amounts of organic vapour modifying cloud albedo and acting to cool climate.
منابع مشابه
Biotic stress accelerates formation of climate-relevant aerosols in boreal forests
Introduction Conclusions References
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عنوان ژورنال:
- Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
دوره 366 1885 شماره
صفحات -
تاریخ انتشار 2008