On April 22, 1970, 20 million people across the United States took to the streets as university and school students joined to demand greater protection for the environment.
It marked the first Earth Day, an event that five decades on is observed by over one billion people across 190 countries.
Despite the passage of time, the message - activists say - remains the same: How do we teach people to better protect our planet?
“There’s not a country on Earth that does it right," says Earth Day Network President Kathleen Rogers.
"We teach a little bit about science, or wetlands or air quality, [but] we almost never teach civic engagement in any country on earth. The very basic issue of education is central to what the Earth Day network does.”
This year, due to the COVID-19 lockdown measures, the event is going digital with a 72-hour long livestream and online messages from Pope Francis, Al Gore, Andrea Bocelli, and others.
But for the network, it is the grassroots supporters that are crucial to success - and they seem to have taken the restrictions in their stride.
Supporters have organised everything from live streams to webinars remotely from their own countries to keep the crucial question of climate change high on the world's agenda.
In 2020, the movement is focusing on the need for political action.
In its latest report Copernicus, the European Union's earth monitoring programme, found that 11 of the hottest years on record were in the last two decades.
Petteri Taalas, Secretary-General of the World Meteorological Organization, said political action is key in turning the tide on climate change.
“Unfortunately we have been heading in the very wrong direction since the 1970s. We have started breaking several less comfortable records and my personal main concern is related to the fact that we have a growing population on this planet and at the same time now, our food production is going to suffer," Taalas told Euronews.
In its last assessment, the Euroopean Environement Agency painted a bleak picture of the fight against the climate emergency in Europe.
"Looking ahead, the current rate of progress will not be enough to meet 2030 and 2050 climate and energy targets. Protecting and conserving European biodiversity and nature remains the biggest area discouraging progress. Of the 13 specific policy objectives set for 2020 in this area, only two are likely be met: designating marine protected areas and terrestrial protected areas."
Lessons from the pandemic
The pandemic and the ensuing lockdowns have had a positive effect on pollution levels - but it is unlikely to last, according to Manfred Fischedick, scientific director of the Wuppertal Institute for Climate Environment and Energy in Germany.
"There is a substantial decrease of energy consumption due to the lockdown (...) for Germany the green house gas emissions have decreased by 6%, a substantial change. But the question is: Is that a long lasting decrease in emissions?
"We think probably not because like after the global economic crisis just 10 years ago and for the recovery process of the economy, which we expect in the next months or next year, emissions will increase substantially like 10 years ago," he said.
For Fishedick the real challenge now is to find a way to persuade businesses to change their ways.
"Governments should put in place stimilus packages that really trigger and set incentives for climate protection investments, such as further developping renewables, investments for renovation of buildings, investments in the chemical industry. (…) A stimulus package can really help to overcome the financial situation of those industries and to help them build up new structures, to be be more resilient and to be more climate friendly in the future."
"A change in behaviour can help to reduce green house gas emissions, if we switch nowadays to working at home for example, it can be done," he said.
Crucially, reaching an 100% cut in green house gas emissions before 2050 isn't just about technology - it is about behaviour.