Mean male height in countries with a high level of GDP is 23 cm greater than in countries with a low level, a difference that has risen by 1.5 cm over the last 30 years. Thanks to a more varied diet rich in animal products, the annual nitrogen and phosphorus intake of people in wealthy countries is practically twice that of those in poor countries.
A new study led by Josep Peñuelas and published in Nature Ecology and Evolution reveals that CO2 abundance in the atmosphere no longer has a powerful fertilizing effect on vegetation. The greening that has been observed in recent years is slowing and this will cause CO2 levels in the atmosphere to rise, thus increasing temperatures and leading to increasingly severe changes in climate.
An extensive review of studies and databases reveals that drought and an increase in temperature are already causing species substitutions, greater aridity, higher forest fire risk, lower soil fertility, and lower water availability, among other negative impacts.
Freshwater ecosystems near densely populated areas have levels of phosphorus which are very high and out of balance with nitrogen levels. This has resulted in altered ecosystem functioning, lower water quality, and has made water conservation more difficult.
Scientists consider it key to understand why droughts kill so many trees and the influence of local forest histories on tree mortality. They also warn that we know very little about the joined effects of different disturbances on each ecosystem, and highlight the necessity to plan research projects covering more time and space.
