America urgently needs to build up its military readiness in the Arctic where melting summer sea ice is setting up a global struggle for resources, a study prepared for the US navy has warned.

The report by the National Academy of Sciences warned that climate change could upset the delicate security balance in the Arctic – even among close allies – and that America is unprepared for the challenges ahead.

"The US military as a whole has lost most of its competence in cold-weather operations for Arctic weather," the report, National Security Implications of Climate Change for US Naval Forces, warned. "In the immediate term, the navy should begin Arctic training and the marine corps should also establish a cold weather training programme."

The report warned that America was currently unprepared to defend its interests in the Arctic. Current submarine sytems would be challenged to operate in the Arctic, the report warned. In addition, the coastguard has just three ice breakers, and these are old and obsolete.

It went on to call on the navy to develop an Arctic observer and research service, with remote sensing equipment such as satellites and drones.

"Even the most moderate predicted trends in climate change will present new national security challenges for the US navy, marine corps, and coastguard," said Frank Bowman, a retired US navy admiral and co-chair of the committee that produced the report.

"Naval forces need to monitor more closely and start preparing now for projected challenges climate change will present in the future," Bowman said.

The report said that it expected large stretches of the Arctic to be ice-free in the summer by 2030, if current rates of ice loss continued.

Competition for oil and gas in the region was bound to increase, the report said. Last year, Scottish oil producer Cairn Energy confirmed it had found oil off the coast of Greenland and one of Nato's senior commanders warned the race for resources could lead to conflict.

"The geopolitical situation in the Arctic region has become complex and nuanced, despite the area being essentially ignored since the end of the Cold War," the report warns.

Between them, the countries sharing the Arctic, which include the US, Canada, Denmark, Norway, Russia, Iceland, Sweden and Finland, have a number of unresolved disputes – over boundaries as well as resources, the report warned.

Although the report acknowledged the potential for conflict in the Arctic was low, it warned: "Co-operation in the Arctic should not be considered a given even among close allies."

The report, four years in the making, reflects growing concern in US military and strategic circles about the security implications of climate change.

In addition to the looming security challenges in the Arctic, the report warned that $100bn in navy installations were at risk from rising sea levels.

All three branches of the US military have been looking at ways to get off oil – through testing biofuels on jet fighters or deploying solar technology in combat zones such as Afghanistan.

The navy has adopted a goal of deriving only 50% of its energy from fossil fuels by 2020. Much of the other half will come from nuclear power, though the navy has also committed to buying stocks of camelina, a crop like canola.

One prime motivator of the switch is cost, and the volatility oil prices. "For every dollar the price of a barrel of oil goes up, the navy spends $31m more for fuel," the navy secretary, Ray Mabus, told a seminar this month. "Our dependence on fossil fuels creates strategic, operational and tactical vulnerabilities for our forces."

The army and marines have also long been concerned that fuel convoys are highly vulnerable to roadside bombs.