Many nuclear power plants were situated next to the ocean to have ready access to huge volumes of water, and sometimes they were built on land that was not very high above mean sea level. These characteristics may cause problems if ocean levels rise the one or two meters that most climatologists project as a result of climate change. The core of the problem resides in nuclear power’s dependence on two things: water and off-site power. Operating and safely shutting down a nuclear power plant require large supplies of cooling water, as well as the power to operate the control panels and the pumps that circulate the water. The Fukushima Daiichi accident happened after the facility lost its connection to the electrical grid and floodwaters caused the backup diesel generators to fail. While an earthquake caused the tsunami that led to the situation, a severe storm coupled with rising sea levels could have the same end result, especially in low-lying areas suffering from increased erosion caused by climate change. Off-site power losses, or "station blackouts," have long been a commonly recognized risk at nuclear power plants. Backup systems have worked in the past, but dramatically rising sea levels, more frequent and intense storms, and the associated erosion that goes with them could make backup electrical systems problematic. To complicate the situation, the same storm and flood that affects a given power plant also interferes with the plant’s communication and transportation networks, hampering the ability of personnel to respond to any crisis at the facility. At a minimum, climate change and the resulting rise in sea level will lead to concerns about the safety and cost of nuclear power plant operation and construction.