ASU and UA scientists collaborated on a study published in international science journal Nature on Thursday that suggests humans are on their way to exceeding Earth’s capacity.

“In surpassing these boundaries, Earth has entered a new era — the Anthropocene era,” according to an ASU press release.

The study proposes the limits of the planet in regard to biodiversity, land use, acidification of the ocean and burning of fossil fuels, an ASU scientist said.

Sander van der Leeuw, director of the School of Human Evolution and Social Change, co-authored the report with 28 other scientists from around the globe.

The report not only shows how the Earth is in danger because of greenhouse gases, but how it is affected by society, van der Leeuw said.

It compiles research completed by the 29 specialists and other scientists who have done climate research in the past.

“The figures we mention in the report are figures that have been looked at by many scientists,” he said.

This report is a part of a series of papers, van der Leeuw said. The authors timed its release just months before the United Nations Climate Change Conference (COP 15) in Copenhagen, Denmark.

One of the main points of the research discusses the Earth’s capacity, van der Leeuw said. Scientists estimate humans will reach the maximum population that the Earth can sustain — about nine billion — this century.

“Population is something that can be calculated quite [accurately] for the future,” he said.

Though van der Leeuw stressed the importance of population growth and its impact on the environment, he also said humans can do a lot to lessen it by using clean and alternative energy sources.

ASU is leading in alternative energy efforts, van der Leeuw said. He applauded Michael Crow, saying he has become a leader in the area by promoting the creation of the Global Institute of Sustainability and promoting alternative energy projects like algae fuel.

There will always be those that doubt the severity of climate change, van der Leeuw said.

“At some point there will be a reckoning, and if we don’t recognize that reckoning we will be in very serious trouble,” he said. “The scientific world is convinced that this is serious.”

Diana Liverman, a professor of geography and development at UA, is also a co-author of the report.

“Our attempt to identify planetary boundaries … has a special resonance in the Southwest, where pressures on biodiversity, land use and water are likely to intersect with climate change to create tremendous challenges for landscapes and livelihoods,” she said in the ASU press release.

Three of the boundaries identified in the paper have already been surpassed, Liverman said in the release. Fossil-fuel use, agricultural pollution and land-use change are what have led to this, she said.

Sustainability graduate student Genevieve Metson said she applauds the writers for being published in Nature, what she called one of the world’s most notable scientific publications. However, Metson said she worries the right people may not see the report.

“Keeping it only within the scientific realm doesn’t pass it on to decision makers,” Metson said. “Copenhagen has to influence scientists.”

Metson said there must be more of a two-way discourse between policy-makers and scientists.

“[Scientists] can’t just say we’re over-carrying capacity,” she said. “We need more action-oriented science.”

Reach the reporter at ndgilber@asu.edu.