Scientists say we’re not making progress

In late 1992, 1,700 scientists from around the world issued a “warning to humanity.” They said humans had pushed Earth’s ecosystems to their breaking point and were well on the way to ruining the planet. The letter listed environmental impacts such as stratospheric ozone depletion, air and water pollution, the collapse of fisheries and loss of soil productivity, deforestation, species loss and catastrophic global climate change caused by the burning of fossil fuels.

“If not checked,” wrote the scientists, led by Union of Concerned Scientists co-founder Henry Kendall, “many of our current practices put at serious risk the future that we wish for human society and the plant and animal kingdoms, and may so alter the living world that it will be unable to sustain life in the manner that we know.”

To mark the letter’s 25th anniversary, researchers now have issued a bracing follow-up. In a communique published Monday in the journal BioScience, more than 15,000 scientists from 184 countries once again found us sorely wanting.

“Humanity has failed to make sufficient progress in generally solving these foreseen environmental challenges, and alarmingly, most of them are getting far worse,” they write, adding: “Soon it will be too late to shift course away from our failing trajectory.”

Global climate change sits atop the letter’s list of planetary threats. Global average temperatures have risen by more than half a degree Celsius since 1992, and annual carbon dioxide emissions have increased by 62 percent — 2 percent this year. Access to fresh water has declined, and forest land has dwindled. Ocean dead zones have increased. The human population grew by a whopping 2 billion, while the populations of all other mammals, reptiles, amphibians and fish have declined nearly 30 percent.

The authors offer 13 suggestions for reining in our impact on the planet, including establishing nature reserves, reducing food waste, developing green technologies and establishing economic incentives to shift patterns of consumption.