Twenty-five years ago, the Union of Concerned Scientists, Cambridge, Mass., and more than 1,700 independent scientists penned the 1992 “World Scientists’ Warning to Humanity,” which called on humankind to curtail environmental destruction and cautioned that “a great change in our stewardship of the Earth and the life on it is required if vast human misery is to be avoided.”

These scientists expressed concern about current, impending or potential damage on Earth involving ozone depletion, freshwater availability, marine life depletion, ocean dead zones, forest loss, biodiversity destruction, climate change and continued human population growth.

With the exception of stabilizing the stratospheric ozone layer, since 1992, “humanity has failed to make sufficient progress in generally solving these foreseen environmental challenges, and alarmingly, most of them are getting far worse,” the study says.

Especially troubling is the current trajectory of potentially catastrophic climate change due to rising greenhouse gas emissions (GHGs) from burning fossil fuels, deforestation and agricultural production, particularly from farming ruminants for meat consumption.

“Humanity is now being given a second notice, as illustrated by these alarming trends,” the study adds. By failing to adequately limit population growth, reassess the role of an economy rooted in growth, reduce greenhouse gases, incentivize renewable energy, protect habitat, re-store ecosystems, curb pollution, halt defaunation and constrain invasive alien species, humanity is not taking the urgent steps needed to safeguard the biosphere.

Examples of steps humanity can take to transition to sustainability include:

(a) Prioritizing the enactment of connected well-funded and well-managed reserves for a significant proportion of the world's terrestrial, marine, freshwater and aerial habitats.

(b) Maintaining nature's ecosystem services by halting the conversion of forests, grasslands and other native habitats.

(c) Restoring native plant communities at large scales, particularly forest landscapes.

(d) Rewilding regions with native species, especially apex predators, to restore ecological processes and dynamics.

(e) Developing and adopting adequate policy instruments to remedy defaunation, the poaching crisis and the exploitation and trade of threatened species.

(f) Reducing food waste through education and better infrastructure.

(g) Promoting dietary shifts toward mostly plant-based foods.

(h) Further reducing fertility rates by ensuring that women and men have access to education and voluntary family planning services.

(i) Increasing outdoor nature education for children, as well as the overall engagement of society in the appreciation of nature.

(j) Divesting of monetary investments and purchases to encourage positive environmental change.

(k) Devising and promoting new green technologies and massively adopting renewable energy sources while phasing out subsidies to energy production through fossil fuels.

(l) Revising our economy to reduce wealth inequality and ensure that prices, taxation and incentive systems take into account the real costs that consumption patterns impose on the environment.

(m) Estimating a scientifically defensible, sustainable human population size for the long term while rallying nations and leaders to support that vital goal.