Despite their diversity, the structure of most tropical rainforests is highly predictable. Scientists have described the various sizes of the trees by a simple mathematical relationship called a power law.

In a new study using data from a rainforest in Panama, researchers determined that competition for sunlight is the underlying cause of this common structure, which is observed in rainforests around the globe despite differences in plant species and geography. The new finding can be used in climate simulations to predict how rainforests absorb excess carbon dioxide from the atmosphere.

A new study finds that human activities are likely contributing far less nitrogen to the open ocean than many atmospheric models suggest. That's generally good news, but it also nullifies a potential side benefit to additional nitrogen, says Meredith Hastings, associate professor of Earth, environmental and planetary sciences at Brown University and one of the study's co-authors.

"People may not be polluting the ocean as much as we thought, which is a good thing," said Hastings, who is also a fellow at the Institute at Brown for Environment and Society. "However, additional nitrogen could potentially stimulate the ocean's ability to draw down carbon dioxide out the atmosphere, which might counteract carbon emissions to some extent. But if we're not adding as much nitrogen, we're not getting that potential side benefit in the carbon cycle."

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.

Two-and-a-half billion people worldwide have no access to safe, durable sanitation systems. Brian Arbogast, director of the water, sanitation and hygiene programme at the Bill & Melinda Gates Foundation, tells SciDev.Net how innovative toilet technologies and business models could help fix this — and help communities cope with the devastation of climate change.

How does climate change impact sanitation?

With sea levels rising, you have flooding that causes huge health problems. As latrines and septic tanks get flooded and waste goes into the streets and streams, it can carry a lot of disease, including cholera, dysentery and typhoid.

The problem is that the world has only one gold standard for sanitation, which is having flush toilets connected to sewer lines, that are further connected to big and expensive wastewater treatment plants. Growing cities that already have water shortages may not have enough water for everybody to bathe and cook, let alone to flush toilets. So, are these cities going to follow the same path we have taken for the last century in developed cities?

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.

Last June, Pope Francis released his much-anticipated encyclical on the environment, Laudato Si’, which received tremendous praise from diverse quarters. The same day, Coral Davenport, writing in the New York Times, noted that the papal encyclical "is as much an indictment of the global economic order as it is an argument for the world to confront climate change." Ms. Davenport quoted me (accurately) as saying that elements of the encyclical were unfortunately "out of step with the thinking and the work of informed policy analysts around the world." In this column, I will elaborate.

First of all, the Pope is to be commended for taking global climate change seriously, and for drawing more world attention to the issue. There is much about the encyclical that is commendable, but where it drifts into matters of public policy, I fear that it is — unfortunately — not helpful.

The long encyclical ignores the causes of global climate change: it is an externality, an unintended negative consequence of otherwise meritorious activity by producers producing the goods and services people want, and consumers using those goods and services. That is why the problem exists in the first place. There may well be ethical dimensions of the problem, but it is much more than a simple consequence of some immoral actions by corrupt capitalists. The document also ignores the global commons nature of the problem, which is why international cooperation is necessary.

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.

The current strong El Niño brewing in the Pacific Ocean shows no signs of waning, as seen in the latest satellite image from the U.S./European Ocean Surface Topography Mission (OSTM)/Jason-2 mission. 

El Niño 2015 has already created weather chaos around the world. Over the next few months, forecasters expect the United States to feel its impacts as well. 

The latest Jason-2 image bears a striking resemblance to one from December 1997, by Jason-2's predecessor, the NASA/Centre National d'Etudes Spatiales (CNES) Topex/Poseidon mission, during the last large El Niño event. Both reflect the classic pattern of a fully developed El Niño.

California's forests are home to the planet's oldest, tallest and most-massive trees. New research from Carnegie's Greg Asner and his team reveals that up to 58 million large trees in California experienced severe canopy water loss between 2011 and today due to the state's historic drought. Their results are published in Proceedings of the National Academy of Sciences.

In addition to the persistently low rainfall, high temperatures and outbreaks of the destructive bark beetle increased forest mortality risk. But gaining a large-scale understanding a forest's responses to the drought, as well as to ongoing changes in climate, required more than just a picture of trees that have already died. 

LSU paleoclimatologist Kristine DeLong contributed to an international research breakthrough that sheds new light on how the tilt of the Earth affects the world's heaviest rainbelt. DeLong analyzed data from the past 282,000 years that shows, for the first time, a connection between the Earth's tilt called obliquity that shifts every 41,000 years, and the movement of a low pressure band of clouds that is the Earth's largest source of heat and moisture -- the Intertropical Convergence Zone, or ITCZ.

"I took the data and put it through a mathematical prism so I could look at the patterns and that's where we see the obliquity cycle, that 41,000-year cycle. From that, we can go in and look at how it compares to other records," said DeLong, who is an associate professor in the LSU Department Geography & Anthropology.