Global Warming
The climate is changing at an unprecedented rate. Yet, for about 10,000 years, the Earth's climate has been remarkably stable. Indeed, since the end of the last ice age, humanity has been able to prosper, taking advantage of stability, to build modern civilization. However, satellites and other technologies today observe an overall trend of warming, with global temperature increasing 1.4°F since 1880. This marks the end of long-term climate stability and perhaps with it human civilization as we know it today.
"There is no question that increased levels of greenhouse gases must cause the Earth to warm in response."
- NASA
The virtual scientific consensus is that global warming is the result of increased human produced greenhouse gases in the atmosphere. A common example is carbon dioxide which has reached a 650,000 year high concentration in the atmosphere, at 303.28 parts per million. When released in the atmosphere, these green house gases trap reflecting infrared energy from the sun, preventing it from leaving earth. This energy heats the globe, having profound impacts on the environments below.
Levels Rising
As Russel McLendon puts it: "The ocean is coming for us." As the Earth continues to heat, ice all around the world is melting and causing sea level rise. Presently sea levels are rising over twice as rapidly as they were only a century ago. Indeed, the latest measures indicate a 3.4 millimeters per year, up from about 1.4 millimeters 100 years ago. Although this seems insignificant, it is important to note that the rate of sea level rise is only going to accelerate as the planet keeps getting warmer. This is because the melting of the ice caps entails further heating as the ice is no longer able to reflect light. Conservative estimates claim 1.3 to 2.0 meters of sea level rise by the end of the century, while more dire estimates predict up to 7.0 meters.
Above: North America if all the world's ice melted. (National Geographic)
Considering the United Nations' report that about 40% of the world's population lives in "coastal areas," the estimates that 1 in 10 people globally live in areas with "risk of flooding" and that over 100 million people live within 1.0 meter of current sea level the human consequences of sea level rise are drastic. If even the most moderate sea level rise predictions are realized there will be tens of millions of environmental refugees by the end of the century. It is hard to find consistent figures, but virtually every estimate pegs the number of future sea level rise refugees at about 60 million, the largest displaced group since World War 2. This attests to the seriousness of the problem, especially for people that live on the coast.