Throughout the history of the Earth there have been several variations in the climate that have led the planet to go through various ice ages, alternating with warmer periods called interglacial eras. These variations are mainly attributable to periodic changes in the orbital structure of our planet, with perturbations due to the periodic trend of solar activity and volcanic eruptions.
Even in the last 2000 years there have been natural variations such as the Roman Warm Period, the medieval climatic Optimum and the Little Ice Age. The predominant causes of Global Warming are to be found in human activity, due to the emissions into the earth's atmosphere of increasing quantities of greenhouse gases, with a consequent increase in the greenhouse effect, and to other factors that are always attributable to human activities.
The Kyoto Protocol, signed in 1997 and which as of November 2009 counts the adhesion of 187 states, aims to reduce these man-made greenhouse gases. The study: Climate warming changes synchrony of plants and pollinators, published on the Proceedings.
Biological sciences, told: "Climate warming changes the phenology of many species. When interacting organisms respond differently, climate change may disrupt their interactions and affect the stability of ecosystems. Here, we used global biodiversity facility occurrence records to examine phenology trends in plants and their associated insect pollinators in Germany since the 1980s.
We found strong phenological advances in plants but differences in the extent of shifts among pollinator groups. The temporal trends in plant and insect phenologies were generally associated with interannual temperature variation and thus probably driven by climate change When examining the synchrony of species-level plant-pollinator interactions, their temporal trends differed among pollinator groups.
O verall, plant-pollinator interactions become more synchronized, mainly because the phenology of plants, which historically lagged behind that of the pollinators, responded more strongly to climate change wever, if the observed trends continue, many interactions may become more asynchronous again in the future.
Our study suggests that climate change affects the phenologies of both plants and insects and that it also influences the synchrony of plant-pollinator interactions."