World Scientists' Warning

The World Scientists' Warning initiatives have been pivotal in drawing global attention to pressing environmental and societal issues through a series of significant communications by the Union of Concerned Scientists and the Alliance of World Scientists. These warnings are renowned for synthesizing scientific consensus on the environmental crises and urging immediate action.

1992: The First Warning

The inaugural World Scientists' Warning to Humanity was issued in 1992, spearheaded by Henry W. Kendall, a prominent physicist and then-chair of the Union of Concerned Scientists. This document was endorsed by over 1,700 scientists, including the majority of Nobel laureates in scientific fields at the time. The warning highlighted the detrimental impact of human activities on the natural world and cautioned against the collision course between humanity and the environment.

2017: A Second Notice

In 2017, the warning was revisited as The World Scientists' Warning to Humanity: A Second Notice, shepherded by William J. Ripple and his colleagues. This document was signed by over 15,000 scientists from 184 countries, underlining the exacerbation of issues such as human overpopulation, ecological overshoot, and the ongoing Holocene extinction. It called for urgent global action to mitigate these crises.

2020: Climate Emergency Declaration

In 2020, the World Scientists' Warning of a Climate Emergency was published, again under the leadership of William J. Ripple. This declaration was supported by more than 11,000 scientists from 153 countries. It emphasized the urgent need for transformative change to address the climate emergency and prevent disastrous outcomes for the planet.

Subsequent Calls to Action

The World Scientists’ Warnings have inspired numerous discipline-specific warnings. For example, in 2025, a paper titled Scientists' Warning: We Must Change Paradigm for a Revolution in Toxicology and World Food Supply, led by researchers including G.E. Seralini, highlighted the need for paradigm shifts in toxicology and the global food supply. Such warnings are critical for galvanizing focused research and action within specific scientific domains.

Related Topics

• Environmental Sciences
• Global Catastrophe Scenarios
• Sustainability
• Biosphere Reserves
• Ecological Footprint

Each of these warnings represents a collective cry from the scientific community, urging immediate, coordinated, and evidence-based action to protect the planet and ensure a sustainable future for all living beings.