In 2017, 15,000 scientists from across the globe signed up to a Warning to Humanity.

The statement spelled out the gravity of our environmental crisis and the urgency of taking action to tackle it. Since then, a further 5,000 scientists have backed the call.

No government has yet heeded it. Support the scientists' call, and pressure governments for action.


"To prevent widespread misery and catastrophic biodiversity loss, humanity must practice a more environmentally sustainable alternative to business as usual ... Soon it will be too late to shift course away from our failing trajectory, and time is running out."

World Scientists’ Warning to Humanity: A Second Notice

The World Scientists' Warning was issued 25 years after a first warning issued by members of the scientific community in 1992, calling for urgent action to avert major environmental problems. The Second Notice found that in almost every respect, that action was not taken and the indicators of impending disaster have become worse.


"We are jeopardizing our future by not reining in our intense but geographically and demographically uneven material consumption and by not perceiving continued rapid population growth as a primary driver behind many ecological and even societal threats"

In addition to actions such as cutting fossil fuel dependency and eating less meat, the warning calls on us all to " limit our own reproduction (ideally to replacement level at most)". Among its 13 recommended actions to avert environmental disaster and collapsing biodiversity are reducing fertility rates through education and family planning, and rallying leaders behind the goal of establishing a sustainable human population.



Since the Warning to Humanity was published online, 5,000 more scientists have endorsed it, taking the total to more than 20,000. The Alliance of World Scientists has also published a letter warning of a climate emergency, supported by 11,000 scientists at the time of writing. If you are a scientist, please add your signature.


Contact political representatives

The collective failure of governments to respond to the Scientists' Warning is a shocking and profound failure of their primary responsibility - to safeguard their own citizens.

Please contact your government directly, and other political representatives to urge them to apply pressure to governments for action.

In the UK, you can write to the Prime Minister via the 10 Downing St website. The Scottish Government can be contacted via and the Welsh Government here.

You can find contact details for MPs, Members of the Scottish Parliament, Welsh Assembly Members and Northern Irish Members of the Legislative Assembly at Write to Them.

Contact political leaders

In the UK, you can write to the Prime Minister via the 10 Downing St website. The Scottish Government can be contacted via and the Welsh Government here.

If you are a US citizen, please contact your elected representatives. You can contact Senators here and Congressional representatives here.

If you are from another country, please contact your minister for the environment.