There were high-fives this week from Detroit to Washington, D.C., as carmakers celebrated record auto sales.

Americans bought 17.5 million cars and trucks in 2015. That's a huge turnaround from 2009, and the Obama administration cheered the rebound as vindication of the president's decision to rescue General Motors and Chrysler from bankruptcy.

"Because of the policy decisions that were made by this administration to place a bet on those workers, America has won, and our economy has been better for it," White House spokesman Josh Earnest told reporters Wednesday.

Meeting the Paris Climate Agreement goal of limiting the increase in the global average temperature to well below two degrees Celsius compared to pre-industrial levels will require increased use of renewable energy and reducing the CO2 intensity of fossil energy use.

The intermittency of when the wind blows and when the sun shines is one of the biggest challenges impeding the widespread integration of renewable energy into electric grids, while the cost of capturing CO2 and storing it permanently underground is a big challenge for decarbonizing fossil energy.

However, researchers from Lawrence Livermore National Laboratory, Ohio State University, University of Minnesota and TerraCOH, Inc. think they’ve found an answer to both of these problems with a large-scale system that incorporates CO2 sequestration and energy storage.

The U.S. Department of Justice, on behalf of the U.S. Environmental Protection Agency, today filed a civil complaint in federal court in Detroit, Michigan against Volkswagen AG, Audi AG, Volkswagen Group of America, Inc., Volkswagen Group of America Chattanooga Operations, LLC, Porsche AG, and Porsche Cars North America, Inc. (collectively referred to as Volkswagen). The complaint alleges that nearly 600,000 diesel engine vehicles had illegal defeat devices installed that impair their emission control systems and cause emissions to exceed EPA’s standards, resulting in harmful air pollution. The complaint further alleges that Volkswagen violated the Clean Air Act by selling, introducing into commerce, or importing into the United States motor vehicles that are designed differently from what Volkswagen had stated in applications for certification to EPA and the California Air Resources Board (CARB).

“With today’s filing, we take an important step to protect public health by seeking to hold Volkswagen accountable for any unlawful air pollution, setting us on a path to resolution,” said Cynthia Giles, assistant administrator for enforcement and compliance assurance at EPA. “So far, recall discussions with the company have not produced an acceptable way forward. These discussions will continue in parallel with the federal court action.”

“Car manufacturers that fail to properly certify their cars and that defeat emission control systems breach the public trust, endanger public health and disadvantage competitors,” said Assistant Attorney General John C. Cruden for the Justice Department’s Environment and Natural Resources Division. “The United States will pursue all appropriate remedies against Volkswagen to redress the violations of our nation’s clean air laws alleged in the complaint.”

A KPMG study shows that the cost of solar power in India, revealed by public auctions, is barely half a cent above that of cheap local coal , writes Chris Goodall, with generators bids falling well below 5p (UK) / 7¢ (US) per kWh. The idea put about at COP21 that India and other poor but sunny countries need coal to develop their economies is fast running out of steam.

When the accountants have fully loaded the network and other costs PV ends up as very slightly cheaper than using lndian-mined coal. And, of course, this advantage will grow as solar gets cheaper.

Commentators eager to arrest the move towards renewable energy are facing increasing difficulties finding arguments for the continued use of fossil fuel.

As 2015 comes to a close, Mongabay is looking back at the year that was. This year saw President Obama reject the Keystone pipeline as historic droughts and a vicious wildfire season wracked the western US and Canada. The world committed to climate action in Paris as Southeast Asia was choking on the worst Indonesian haze in years, Shell aborted its plans to drill in the Arctic for the “foreseeable” future, and ExxonMobil is being investigated for lying to the public about climate risks. Here, in no certain order, are the top 15 environmental stories of 2015.

Though it seems to be oddly absent from the mainstream media headlines, a massive methane gas leak in Southern California’s Aliso Canyon has prompted thousands of evacuations and, since Oct. 23, has pumped over 150 million pounds of the greenhouse gas into the atmosphere. Even though the owners of the methane well, Southern California Gas Co., say this week that they have finally discovered the pipe associated with the leak, it will likely be months before a seal is entirely in place.

To truly underscore the seriousness of the Porter Ranch gas leak, the Environmental Defense Fund released an infrared aerial video this week showing the tremendous, continuous release of methane:

Methane gas, in its natural state, is also odorless. However, for safety reasons, foul-smelling additives are artificially included with the gas. In Porter Ranch, a Los Angeles neighborhood and the site of the leak, the additive smell’s intensity has affected the heath of many of residents — nose bleeds, nausea, headaches and dizzy spells have been reported.

The U.S. wind power industry is celebrating after reaching a new milestone in November: 70 gigawatts (GW) of generating capacity.

"That's enough to power about 19 million homes," says Michael Goggin, senior director of research at the American Wind Energy Association (AWEA).

Fuel economy is at record highs and carmakers have surpassed strict greenhouse gas emissions standards for the third straight year, according to the Environmental Protection Agency, which released a pair of annual reports about the U.S. fleet of cars and trucks Wednesday.

Overall, fuel economy for vehicles in the U.S. did not budge from last year's record high of 24.3 miles per gallon, the EPA says. The figure includes a new high of 20.4 mpg for trucks, vans and SUVs from model year 2014.

The U.S. has a chance to be a leader in renewable energy deployment given its sheer size and resources. And some states are leading the way. Olivet Nazarene University’s engineering department ranked the top 10 green states in terms of renewable energy. How does your state stack up? Did it make the list? Read on to find out.

Lawrence Livermore researchers and collaborators have found that most climate models overestimate the increase in global precipitation due to climate change.

Specifically, the team looked at 25 models and found they underestimate the increase in absorption of sunlight by water vapor as the atmosphere becomes moister, and therefore overestimate increases in global precipitation.

The team found global precipitation increase per degree of global warming at the end of the 21st century may be about 40 percent smaller than what the models, on average, currently predict.