A reportcommissioned by the World Bank says the Earth is on a path to a climate that is 4 degrees Celsius warmer by the end of the century. In order to slow this down, world leaders will have to do more to reduce greenhouse gas emissions than they're currently doing.From the release: The report says that the 4°C scenarios are potentially devastating: the inundation of coastal cities; increasing risks for food production potentially leading to higher under and malnutrition rates; many dry regions becoming dryer, wet regions wetter; unprecedented heat waves in many regions, especially in the tropics; substantially exacerbated water scarcity in many regions; increased intensity of tropical cyclones; and irreversible loss of biodiversity, including coral reef systems.Four degrees Celsius is a huge increase...it means the world could be on average 7.2 degrees Fahrenheit warmer by 2100. The report says with careful policy changes, that warming could be held to 2 degrees Celsius, which would still have an effect on crops and ocean levels.If courses aren't changed, this warming will predominantly affect the poor, which is why the World Bank is weighing in. The effects of climate change will likely affect low-income individuals, who can't necessarily relocate from the coastline or rebuild after their homes are destroyed. But there are also serious national security implications, as droughts make food more expensive and harder to get and countries compete for water resources.The United Nations is also expected to issue a scientific assessment on climate change in 2014, and the World Bank says it doesn't consider its report a substitute.Read the report here.