The concerns of global warming have been well documented, from its potential impact on wildlife to how it can affect public health. And as ice caps are melting and temperatures are rising under one of the warmest years in history, the Arctic is getting closer to an ice-free summer, which may come by the 2050s, according to a team of American and Chinese scientists.
In a recent study published in the journal Proceedings of the National Academy of Sciences, University of Albany Professor Jiping Liu and his team used climate model simulations to predict that the Arctic may reach an ice-free state as early as 2054. The area would be considered essentially ice-free when ice coverage is less than 1 million square kilometers, or about 386,000 square miles. In September 2012, ice coverage hit a new record low of about 1.3 million square miles.
During the month of September, which is summertime in the Arctic, ice coverage is typically at its lowest, and has been declining drastically over the last several decades, a decrease of about 40 percent since the late 1970s. In just the last few years, from 2007 to 2012, the Arctic has seen the lowest September ice cover in history, the report says.
"An ice-free Arctic would have a significant impact on the ocean's ecosystems, biogeochemical feedback, and extreme weather and climate in the mid- and high-latitudes," Liu said in a statement. "It will also affect Arctic maritime and commercial activities, including shipping, transport, and energy exploration."
The American Meteorological Society reported this week that 2012 was one of the 10 warmest years worldwide on record since the 1800s and the warmest ever for the United States (see excerpts from the AMS report).The average temperature for the United States in 2012 was about 55 degrees Fahrenheit – up from a previous record high of about 54.3 degrees Fahrenheit in 2006 and higher than the average for the entire 20th century.
While climate change is expected to have adverse consequences for wildlife, weather patterns and the environment overall, warming temperatures and lower ice levels will also have an impact on commercial travels and even employment.
The National Oceanic and Atmospheric Administration found this week that climate change and human-made stressors can negatively affect the nation's estuaries, the places where rivers meet the sea.
Not only are estuaries a home to fish and shellfish, they are also an important source of food, jobs and storm protection for nearly 40 percent of all Americans, or 123 million people, according to NOAA. About half of the nation's gross domestic product – $6.6 trillion – comes from these areas, which also support more than 51 million jobs.
The report points to four estuary reserves – one each in Georgia, South Carolina, Massachusetts and near the Tijuana River on the California-Mexico border – that are more biologically sensitive to climate change than others. Factors such as rising sea levels, more frequent and intense precipitation and drought can negatively affect these areas.
And some estuaries, particularly along the West Coast and the Gulf of Mexico, have higher levels of social sensitivity to these changes, in part because the areas surrounding them have more jobs that depend on natural resources, lower average income levels, higher percentages of minority populations and higher percentages of people lacking a high school diploma.
"This information is important to helping coastal managers and local community leaders make informed decisions about the best ways for coastal communities to adapt to climate change," said Dwight Trueblood, a co-author of the estuary report and NOAA program manager, in a statement.