In 1907, the US Navy\u2019s Great White Fleet of 16 steam-powered, steel-hulled battleships circumnavigated the Earth in a dramatic show of America\u2019s technological advancement to global threats of the time [1]. 105 years later, the Navy debuted its Great Green Fleet, a carrier strike group operating on a petroleum-biofuel blend, in a show of force against America\u2019s newest threat \u2013 global climate change [2]. With the safety of global supply chains at stake, and threats to its own logistics operations imminent, the US Navy has been preparing for climate change for more than a decade.<\/p>\n
Part of the Navy\u2019s mission is to protect freedom of the seas around the world, which allows global supply chains to exist. Climate change stands to complicate that mission as environmental conditions are expected to leave waterways open longer [3]. Additionally, Arctic warming is expected to increase global competition for resources in the region, which contains 22 percent of the world\u2019s untapped oil and gas deposits [4]. Increasing shipping traffic combined with competition from other nations will require more Navy ships in operation to protect American assets.<\/p>\n
Navy officials also need to consider the effects that climate change will have on its own supply chain. Increased operations for US warships will result in higher fuel consumption and cost. The Navy already accounts for 30 percent of Department of Defense energy use [5]. When the price of a barrel of oil increased by $30 several years ago, the Navy took a billion-dollar hit to its budget [6]. Fossil fuel consumption is expensive and unpredictable in a world that requires more Navy ships due to climate change.<\/p>\n
As climate change causes sea levels to rise at an accelerating pace, Navy officials must be prepared to respond to the adverse effects that this will have on its logistics ashore. For instance, a three-foot rise in sea levels, which is expected by 2100 in some moderate models, will cause damage to 55 naval installations valued at $100 billion [7]. Naval Station Norfolk, home to the Atlantic Fleet, has seen sea levels rise 14.5 inches in the past century and already deals with periodic flooding [8] [9].<\/p>\n
In response to the threats posed by global climate change, the US Navy has spent the past decade tweaking its strategy to prepare for future unknowns. Much of this strategy revolves around fossil fuel consumption. Its 2010 Quadrennial Defense Review stated, \u201cenergy security for the Department [of Defense] means having assured access to reliable supplies of energy and the ability to protect and deliver sufficient energy to meet operational needs\u201d [5]. As such, the Navy has invested heavily in biofuel as a method to not only do its part to mitigate climate change, but also increase fuel efficiency and reduce cost uncertainty associated with fossil fuels. By 2020, half of the Navy\u2019s energy consumption is expected to come from alternative sources [5]. The Navy has also experimented with new forms of propulsion to improve costs while increasing operating time at sea. The USS Makin Island, an amphibious assault ship the size of an aircraft carrier, has a hybrid-electric drive that saved the Navy $2 million on its maiden voyage [6].<\/p>\n