What Will the Climate Be in the Future?
Attributing climate change to human activity has been the subject of debates ever since the creation of the IPCC. It will take another few years, probably a decade, perhaps more, for this to become an uncontested assertion. Continuing to acquire quality data, better understand the role of aerosols, better identify the natural causes, know more precisely the sensitivity of the climate—in other words its reaction vis-à-vis a modification in the radiative forcing, as well as its natural variability and causes—are the directions in which we must collectively progress. However, there is a near certainty that we must face when we turn to the future: the climate will continue to warm. Why is this? Quite simply because even if, by waving a magic wand, we were able to instantly stabilize the greenhouse effect, the climatic system has an inertia such that it would still warm by an amount almost equivalent to what has occurred over the twentieth century. In fact, limiting warming to 2°C, even compared to the climate at the end of the twentieth century, is a true challenge, whose different facets we will examine in a later chapter.
Let’s first look at a climatic future in which the need to stabilize the greenhouse effect would not be taken into account. This is in fact the process widely undertaken by the IPCC experts in the 2007 report of the scientific group, which we will look at broadly here for that which involves the global climate and in more detail for that which concerns our white planet: glaciers, sea ice, frozen ground. But we will also look at the sea level, whose rise is largely associated with the behavior of polar ice caps and inland ice sheets, and at the Gulf Stream, whose evolution is strongly influenced by that of the climate in high latitudes.