Humanity is in the existential danger zone, scientists warn

Climate change and high rates of extinctions of animals and plants are pushing the Earth into a danger zone for humanity, said a scientific report card about mankind’s impact on nature.

In a new study published in the journal Science, an international team of 18 researchers argue the most important “planetary boundary” is the level of carbon dioxide in the atmosphere, followed closely by the rate of species extinction.

The other “planetary boundaries” the planet’s exceeding are the rate of species extinction and the flow of nitrogen and phosphorous, altered by agricultural fertilization and loaded into the ocean.

A 2009 paper established the concept of “planetary boundaries” for the earth system. The premise is to establish what’s meant by healthy, and to encourage policies that keep human activity within the boundaries. This team says exceeding the boundaries will disrupt the function of the planet, deteriorate the well-being of life on it, and eventually change how we can live.

The newest study makes more clear that scientists are uncertain about exactly how well we’re doing on some of the planetary boundaries. For example, the study concludes that diversity of species is diminishing, but says that we lack adequate knowledge to determine the severity

Scripps Institute of Oceanography Climatologist Veerabhadran Ramanathan says it’s not surprising that the study’s findings could produce anxiety.

“It’s just a terrific way to respond because we’re changing all of this without knowing what we are doing,” Ramanathan says.

Members of the research team say they aren’t making policy recommendations, but that the purpose of the study is to raise awareness about the larger questions human activity creates.

Agencies/Canadajournal