A proposed oil pipeline between the US and Canada, the Keystone XL project, has been frought with controversy. In January, President Barack Obama spoke against it amid protests about its impact on the environment. But in March, he endorsed it. "Today, I'm directing my administration to cut through the red tape, break through the bureaucratic hurdles, and make this project a priority," he said.
This file photo shows crude oil from the Deepwater Horizon oil seeping out from a ruptured well in the Gulf of Mexico in 2010. In March this year, BP agreed to settle lawsuits brought by more than 100,000 fishermen who lost work, cleanup workers who got sick and others who claimed harm from the 2010 disaster, the worst offshore oil spill in US history.
Chalara fraxinea fungus has infected woodlands across Europe, devastating ash trees. In Britain, officials have imposed an import ban but experts say the country's 80 million ash trees remain at risk. "Experts fear it is the greatest threat to British trees since 25 million trees were killed by Dutch Elm disease 30 years ago," said Mary Creagh, the Labour Party's shadow environment secretary.
The United Nations Conference on Sustainable Development (UNCSD), also known as Rio+20, was the third international conference on sustainable development aimed at reconciling the economic and environmental goals of the global community. Hosted in Rio de Janeiro from June 13-22, the summit fell short of what many had hoped it would achieve. Many environmentalists called it a failure.
In August, researchers reported in the journal "Scientific Reports" that abnormalities were found in butterflies near where the Fukushima nuclear power plant melted down in 2011. "We have reached the firm conclusion that radiation released from the Fukushima Daiichi plant damaged the genes of the butterflies," said Joji Otaki, associate professor at Ryukyu University.
In August, seven of the world's rarest rhinoceroses were spotted in a national park in Indonesia - the first time the creatures have been seen in 26 years. Six females and one male rhino are now known to live in the Mount Leuser National Park, on the northern tip of the island of Sumatra. But deforestation is still pushing the rhinos toward extinction.
On September 1, a new law prohibiting the sale of incandescent light bulbs in the European Union went into effect. Considered wasteful as they convert only five percent of the energy they use into light, the last bulbs disappeared from shelves by the end of the month. Replacing them were LEDs and compact fluorescent lamps, which use up to 90 percent less energy.
During the summer, as droughts scorched continents throughout the Northern Hemisphere, an even bigger debacle unfolded further north. Arctic sea ice levels reached a new record low on September 16 at 3.41 million square kilometers (1.32 million square miles) - about half of normal. It increased fears that such melts could soon become normal.
Protesting village women shout slogans as they stand in water at Ghogal village in the central Indian state of Madhya Pradesh in September. The protestors were demanding compensation and rehabilitation for villagers whose homes will be submerged under water after opening the gates of the Omkareshwar dam because of rise in water levels of the Narmada River.
When Hurricane Katrina hit New Orleans, billions in damage was caused, in addition to the thousands of lives that were lost. This past October, Superstorm Sandy slammed into New York City, inundating roadways, blasting structures with high winds and causing widespread destruction. The New York Stock Exchange was forced to shut down for consecutive days for the first time since the 1800s.
While protests such as this one in Berlin helped convince Germany to close its nine nuclear power plants by 2022, the country has been searching for an energy alternative. Pressure has risen throughout 2012 to find a suitable replacement. One proposal has been hydraulic fracturing, otherwise known as fracking, but that too has its risks.
In December, protestors came out in droves in Qatar as countries discussed strategies for continuing the fight against global warming. At the conference in Doha, an agreement did end up being reached to extend the Kyoto Protocol, the groundbreaking 1997 agreement that calls for cuts to harmful greenhouse gas emissions, until 2020.
In terms of environmental impact, 2012 was monumental. DW takes a look back at some of the biggest environment stories of the year from around the globe.