The report is a wake-up call for Americans to take climate change seriously, and to launch significant efforts to reduce greenhouse gas emissions in order to hedge against possible negative impacts and surprises. Even if the impacts ultimately manifest differently from what the report projects, what is clear is that everyone will experience some changes. Climate change is not science fiction. In some regions, like Alaska, the first impacts of warming are here, now. It is also very likely that more rain will come in heavy downpours, increasing the risk of floods.
Natural ecosystems are highly vulnerable to the projected rate and magnitude of climate change.
The resources lost through the disappearance or fragmentation of certain ecosystems are likely to be costly or impossible to replace. Those ecosystems have very limited options to adapt to climate change and are already stressed through air and water pollution, habitat fragmentation, and overuse. A rise in sea level will heighten threats to buildings, roads, power lines, and other infrastructure along coastal areas. Sea-level rise is very likely to cause the loss of some barrier beaches, islands, and wetlands, and worsen storm surges and flooding during storms. Overall, US crop productivity is forecast to increase over the next few decades, but the gains will not be uniform across the nation.