[2] It was sometimes offered in opposition to the Heidelberg Appeal—also signed by numerous scientists and Nobel laureates earlier in 1992—which begins by criticizing "an irrational ideology which is opposed to scientific and industrial progress, and impedes economic and social development."
[5] A 2021 update to the 2019 climate emergency declaration focuses on 31 planetary vital signs (including greenhouse gases and temperature, rising sea levels, energy use, ice mass, ocean heat content, Amazon rainforest loss rate, etc), and recent changes to them.
They point to six areas where fundamental changes need to be made:[8] (1) energy — eliminating fossil fuels and shifting to renewables; (2) short-lived air pollutants — slashing black carbon (soot), methane, and hydrofluorocarbons; (3) nature — restoring and permanently protecting Earth's ecosystems to store and accumulate carbon and restore biodiversity; (4) food — switching to mostly plant-based diets, reducing food waste, and improving cropping practices; (5) economy — moving from indefinite GDP growth and overconsumption by the wealthy to ecological economics and a circular economy, in which prices reflect the full environmental costs of goods and services; and (6) human population — stabilizing and gradually reducing the population by providing voluntary family planning and supporting education and rights for all girls and young women, which has been proven to lower fertility rates.At the 30th anniversary of the World Scientists' Warning to Humanity, a second update to the climate emergency declaration concluded that "We are now at 'code red' on planet Earth".
Secondly, the warning urges policy-makers to "implement population policies with two key female empowerment components," primarily improving education for young women and girls and providing high-quality family-planning services to all.
It also posits that a sustainable human population, which according to environmental analysts is "one enjoying a modest, equitable middle-class standard of living on a planet retaining its biodiversity and with climate-related adversities minimized," is between 2 and 4 billion people.
The warning also advocates for combatting poverty, patriarchy and overconsumption by the affluent, and calls for a global wealth tax to be levied primarily against "wealthy nations, industries and people who have benefitted the most from humanity's massive-scale historical and contemporary use of fossil fuels" in order to expand "clean sanitation and water availability, food sovereignty, and electrification via renewables."