|
The World in 2050: Four Forces Shaping Civilization's Northern FutureOut of perhaps seven million eukaryote species found on Earth, nearly half of all vascular plants and one-third of vertebrates are confined to just twenty-five imperiled БЂњhot spots,БЂ«mostly in the tropics and comprising just 1.4% of the worldБЂ™s land surface.307 Even in the far North, a specialized ecosystem adapted to frigid cold will be under attack by advancing southern competitors, pests, and disease. It is possible that the vast boreal forestБЂ”girdling the northern high latitudes from Canada to SiberiaБЂ”might convert to a more open, savannah-like state.308 But total primary productivityБЂ”meaning plant biomass, the bottom of the food chainБЂ”will be ramping up. Certain mobile southern invaders will enjoy growing viability in a vast new territory that is larger, less fragmented, and less polluted than where they came from. Longer, deeper penetration of sunlight into the sea (owing to less shading by sea ice) will trigger more algal photosynthesis, again increasing primary productivity and reverberating throughout the Arctic marine food web ...» |
Код для вставки книги в блог HTML
phpBB
текст
|
|