The University of Florida study shows that red cedars are among the first to go, while cabbage palms delay death longer. Researchers said other factors may play a role in the deaths, and that one remaining question is whether human activity has contributed to global warming, possibly accelerating the rising sea level. Seems it's not just the forests of the tropics that soak up all those greenhouse gases. As a sign that planting trees in dry places might benefit the environment, researchers have found that increased levels of greenhouse gases have led to faster tree growth in arid regions, according to a story in this week's New Scientist magazine. Looking at tree rings, Xiahong Feng of Dartmouth College found that the rise in atmospheric carbon dioxide the past 200 years has made trees in dry places grow faster.
Plants soak up carbon dioxide, combining it with water to create other chemicals.
In regions where lack of water limits tree growth, the total biomass may have increased, the story reports, suggesting that arid forests may be more important to the study of global warming than previously believed. But some particles seem to have the opposite effect, by creating more clouds which reflect sunlight back to space. The phenomenon affects climate locally, and probably regionally, say researchers from Italy's Consilio Nazionale delle Ricerche and the University of Washington, who reported their findings in last week's journal Nature. Organic particles, such as those produced when agricultural waste is burned, appear to decrease the surface tension of tiny aerosols in the atmosphere, allowing more cloud droplets to form. The result could be a 1 percent increase in reflected sunlight.