Debate continues over how much oil remains in the Gulf from last April's spill — but one thing we do know, thanks to a new study, is that in addition to the oil visible at the surface, the leaking well produced a subsurface plume of oil 1,100 meters deep.

Volcanoes explosively erupt in Guatemala and Ecuador; meanwhile, an earthquake rocks Vanuatu, Iceland prepares for another possible eruption, and the U.S. continues to battle the oil spill in the Gulf.

Marine mammals live in a world of sound. But their clicks and calls are not the only underwater noises: Oil and gas exploration, seafloor mapping, and ship and submarine navigation have increased dramatically over the past few decades. Now, Exxon Mobil and eight other oil and gas companies are investigating how humans can still explore the oceans — while turning down the volume.

In 1983, the erstwhile surface mine Gateway Hill, part of Canada's Athabasca Oil Sands Deposit, resembled a pockmarked, barren moonscape. Today, after years of reclamation effort, Gateway Hill is thickly forested and filled with wildlife — and as the first oil sands mine site to be certified by the government to be at pre-mine condition, it is a model for new and ongoing reclamation projects.

Inexpensive, abundant and relatively clean: EARTH commenter and Stanford geophysicist Mark Zoback makes the case for natural gas to become a key part of U.S. energy policy.

With the future of energy so uncertain, only a fool would boldly make predictions, according to EARTH regular contributor Michael E. Webber. So here, he gives his "fool's take" on the future of energy.

For our end-of-year issue, EARTH asked several of its regular contributors to look into their crystal balls and anticipate what will happen in the future in their various fields. In this comment, Rasoul Sorkhabi gives his take on the energy scenario for 2010, both in the United States and around the world.

Instead of debating whether oil production is about to go into terminal decline, the author writes, let's just make "peak oil" — and therefore a post-peak oil world — happen as fast as possible.

Despite all of our efforts to date, no domestic, sustainable, scalable, affordable and environmentally friendly alternative for transportation fuels has emerged. Is it time to give coal-to-liquids a chance?

Unassuming algae could be the ultimate in “green” fuel, powering everything from cars to jets. But if it's going to compete with oil and gas, algae can't stay in the backyard — commercialization will require investment in molecular genetics research, algal physiology and engineering.

President Barack Obama today said his administration plans to make it easier for states to set their own fuel emissions standards, paving the way for California to finally receive a waiver on the issue from the EPA after years of legal quagmire.

According to EIA's latest Short-Term Energy Outlook report, the global demand for oil dropped dramatically this year — but will plunge even further next year.

With the world's largest natural gas reserves and the eighth-largest oil reserves, energy is critical to Russia's economy. But does Russia's aggressive posture threaten global energy supplies?

Been reading about oil speculation and "short-selling" but confused by the jargon? We explain it all for you.

Whether we've already reached "peak oil" or not, oil still is and will likely remain the world's primary source of energy for the next few decades, scientists say. We just haven't significantly ramped up renewables yet.