The longer we delay addressing environmental problems, the more difficult it will be to resolve them. Although we've known about climate change and its potential impacts for a long time, and we're seeing those impacts worsen daily, our political representatives are still approving and promoting fossil fuel infrastructure as if we had all the time in the world to slow global warming.

We can't say we weren't warned. In 1992, a majority of living Nobel prize-winners and more than 1,700 leading scientists worldwide signed a remarkable document called World Scientists' Warning to Humanity.

It begins, "Human beings and the natural world are on a collision course. Human activities inflict harsh and often irreversible damage on the environment and on critical resources. If not checked, 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 we will be unable to sustain life in the manner that we know. Fundamental changes are urgent if we are to avoid the collision our present course will bring about."

It then outlines critical areas where the collision was and is still occurring: the atmosphere, water resources, oceans, soil, forests, species extinction and overpopulation. In the 25 years since it was published, the problems have worsened.

The document grows bleak: "No more than one or a few decades remain before the chance to avert the threats we now confront will be lost and the prospects for humanity immeasurably diminished. We the undersigned, senior members of the world's scientific community, hereby warn all humanity of what lies ahead. A great change in our stewardship of the earth and life on it is required, if vast human misery is to be avoided and our global home on this planet is not to be irretrievably mutilated."

Now, as monthly and annual records for rising global average temperatures continue to break, as extreme weather events become more frequent and severe, as refugees overwhelm the capacity of nations, and as tipping points for climatic feedback loops and other phenomena are breached, the need to act is more urgent than ever.

The warning suggests five steps needed immediately. That was a generation ago. They can still help prevent the worst impacts:

1. "We must bring environmentally damaging activities under control to restore and protect the integrity of the earth's systems we depend on." It specifically mentions reducing greenhouse gas emissions and air and water pollution. It also highlights the need to address deforestation, degradation and loss of agricultural soils and extinction of plant and animal species.

2. "We must manage resources crucial to human welfare more effectively." This one is obvious. Finite resources must be exploited much more efficiently or we'll run out.

3. "We must stabilize population. This will be possible only if all nations recognize that it requires improved social and economic conditions, and the adoption of effective, voluntary family planning."

4. "We must reduce and eventually eliminate poverty."

5. "We must ensure sexual equality and guarantee women control over their own reproductive decisions."

The warning recognizes that we in the developed world are responsible for most global pollution and therefore must greatly reduce overconsumption while providing technical and financial aid to developing countries. This is not altruism but self-interest, because all of us share the same biosphere. Developing nations must realize environmental degradation is the greatest threat to their future, while rich nations must help them follow a different development path. The most urgent suggestion is to develop a new ethic that encompasses our responsibility to ourselves and nature and that recognizes our dependence on Earth and its natural systems for all we need.

The document ends with a call for support from scientists, business and industrial leaders, religious heads and all the world's peoples. Like Pope Francis's groundbreaking 2015 encyclical, Laudato Si, the World Scientists' Warning to Humanity was an attempt to galvanize the world to recognize the dangerous implications of humanity's path and the urgent need for change.

Forewarned is forearmed. We can't let the lure of the almighty buck blind us. We must come together, speak up and act for the good of all humanity.