Whether climate will change a little more or a lot more depends primarily on our actions. The more heat-trapping greenhouse gases we emit, the more climate change we will experience. Rapid and substantial reductions are needed to bring climate change under control.
The Framework Convention on Climate Change, an international agreement signed by 192 countries, calls for avoiding “dangerous human interference with the climate system.” Many analysts think we have already crossed into “dangerous” territory and that the goal now should be to avoid catastrophic climate change that could lead, over the coming decades and centuries, to the uprooting of hundreds of millions of people, the eventual drowning of many coastal cities, the disruption of agricultural climates, and reductions in water availability.
The European Union and many scientific organizations have concluded that avoiding these outcomes will require limiting global average warming to 2°C (3.6°F) relative to pre-industrial levels. If this threshold is exceeded, negative impacts are projected to become more severe, widespread, and irreversible, and dangerous tipping points may be crossed. A global rise of 2°C means that some continental interiors will see temperatures rise about twice that much, with even larger increases in polar regions.
As we consider a 2°C target, it is worth noting that a 1°C increase has already had significant impacts including the melting of ice on land and sea, rising sea level, and changes in animal and plant distributions.
While 2°C is a defensible target, in fact there is no precise point below which we are safe and above which we are in danger – but we do know that the risks increase as the temperature rises. The science tells us that we must reduce fossil fuel emissions and deforestation as much as possible, as quickly as possible, with the long-term goal of eliminating them entirely.
If 2°C is the target, then global emissions would need to peak within a decade and decline by 50 to 80 percent by 2050. So that developing countries can grow, industrialized countries, responsible for the bulk of the greenhouse gases now in the atmosphere, would need to reduce their emissions by more than 80 percent by 2050.