They said humans had pushed Earth's ecosystems to their breaking point and were well on the way to ruining the planet. At the time, 1,500 scientists said they were anxious how climate change and population growth, as well as losing ozone, fisheries, and biodiversity, could hurt the planet. The authors said: "To prevent widespread misery and catastrophic biodiversity loss, humanity must practice a more environmentally sustainable alternative to business as usual".
Unfortunately, the findings confirmed things haven't gotten much better.
To mark the letter's 25th anniversary, researchers have issued a bracing follow-up.
In a cautionary message, 15,364 scientists from 184 countries signed the letter published this Monday by the journal BioScience. Once again, they find us sorely wanting. They note that the overwhelming majority of the previously outlined threats remain and "alarmingly, most of them are getting far worse".
Over 15,000 scientists support this notion, serving as a prophetic warning that follows a similar notice issued in 1992.
While the number of limited resources is decreasing, the number of worldwide population is increasing. The human population grew by a whopping 2 billion, while the populations of all other mammals, reptiles, amphibians and fish have declined by almost 30 percent. With the exception of a stabilized stratospheric ozone layer, the news is not good.
Progress in some areas-such as a reduction in ozone-depleting chemicals and an increase in energy generated from renewable sources-shows that positive changes can be made, the authors wrote.
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.
Ripple and his colleagues have formed a new independent organization, the Alliance of World Scientists, to be a collective voice on environmental sustainability and human well-being.
Back in 1992, a group of scientists signed a paper warning people about the consequences that were coming due to pollution and threats to the Earth. Those who signed this second warning aren't just raising a false alarm. In fact, they are doing the opposite totally: acknowledging the obvious signs that "we are heading down an unsustainable path".