The lockdown gave people a "glimpse" of a new and different world, with less pollution and more social cohesion, the leaders of the Green Party have said.
Addressing their annual conference, Jonathan Bartley and Sian Berry said the virus had exposed just how unequal the country was and how its economic system was "not fit for purpose".
A green recovery was vital to building resilience and fairness, they said.
They also vowed to stand foursquare with climate and anti-racism activists.
Speaking in London, Mr Bartley said the Greens would continue to support protest movements such as Extinction Rebellion or Black Lives Matter even if they were not "neat and tidy or well-behaved".
The party, he said, was the "political arm" of a much wider social movement which had consistently "dissented" from the mainstream and been proven right.
And Ms Berry said the need to build alliances between different organisations, ranging for LGBT groups to ex-miners, had never been greater as the fight for climate, economic, social and racial justice was "not divisible".
Like other political parties, the Green Party of England and Wales has been forced to move their conference online this year.
Their two co-leaders, who were re-elected for a second term last month, on a joint ticket, addressed activists on the first day of a week of online debates and discussions.
Mr Bartley said the government's failures had left the country ill-prepared to face the pandemic, leaving the poorest and most vulnerable in society to suffer disproportionately.
He called on the government to strip outsourcing giant Serco of its Test and Trace contracts and for responsibility to be given to local councils and public health leaders.
The virus had caused "heartbreaking" suffering to so many, he said, but the nationwide lockdown - when much of the economy shut down and all but essential workers stayed at home - had shown a different path for the UK.
He said businesses had demonstrated they could adapt to new ways of operating, communities "came together in solidarity", the value of key workers was properly recognised, rough sleepers were taken off the streets and tenants were protected from eviction.
"We saw a different world might be possible in lockdown...we had a glimpse of something new," he added.
Ms Berry said the £1tn in investment the Greens called for at last year's election to build a more sustainable economy and to allow the UK to go carbon neutral by 2030 was needed even more now.
The combination of a "green new deal", in everything from energy to transport, and weekly a universal basic income payment to every person in the country would help the country "break free" from its old models.
"We have to be ready to weather the storm and build a shelter for the next one," she said, pointing out that the party's "bold ideas" have often turned out to be "the common sense of tomorrow".
"Our prevailing economic system is just not built for resilience in a crisis," Mr Bartley added.
Its co-leaders said the party, which has only one MP but hundreds of councillors across England and Wales, had to become more disciplined in "having and using power".
They said the party was hoping for a big increase in representation in next year's council elections in England as well as pushing to win its first mayoral election.