Nicola Sturgeon has said she believes the world is facing a climate emergency and pledged to speed up efforts to achieve zero carbon emissions.

Following similar moves by the Labour leader, Jeremy Corbyn, this weekend, the Scottish first minister said she was declaring the emergency because the science showed global warming was worsening.

She told the Scottish National party’s spring conference in Edinburgh that if the UK’s expert advisory committee on climate recommended more urgent action to cut CO2 emissions in a report later this week, her government would act.

In Holyrood last month, SNP MSPs voted with other parties against a Scottish Green party motion calling a climate emergency, while the Scottish parliament has been targeted three times this year by Extinction Rebellion protesters.

“I am making this public promise to the young people I met, and to their entire generation,” Sturgeon said. “If that advice says we can go further or go faster, we will do so. Scotland will lead by example.”

In a speech focusing heavily on the SNP’s bid to become Scotland’s main anti-Brexit party in the European elections next month, Sturgeon offered few new details about the timescale for a second independence referendum, focusing instead on measures to build the popular case for independence.

She made several domestic policy announcements including a £150m scheme to co-fund mortgage deposits for first time buyers with new loans, and a promise to provide £250 grants for poor children going to nursery, with a second grant once they start at primary school.

The Guardian revealed last week the island of Arran was suffering a housing crisis, due to a boom in holiday lets, and Sturgeon said new proposals to control short terms lets in places such as Arran and Edinburgh would be unveiled soon.

Sturgeon cited opinion polls this weekend that give the SNP a substantial lead over the other parties in Scotland, of between 23 and 26 points in all three legislatures: Holyrood, Westminster and the European parliament.

Nicola Sturgeon (@NicolaSturgeon) Today’s @YouGov poll in @thetimes is amazing. 23 point lead for @theSNP in Westminster election, 24 point lead for @ScotParl and 25 point lead for Euro elections. And #Indy at 49%. Happy #SNP19

Two polls by YouGov and Panelbase this weekend suggest the SNP will win three or four or Scotland’s six seats in the European elections next month, reducing Labour and the Tories to one each. YouGov showed the SNP has 40% of the vote for a European election.

“As voters go to the polls for the European elections on May 23 our message will be clear and direct. And unlike Labour’s, it will be unambiguous,” Sturgeon said. “Scotland’s not for Brexit, Scotland’s for Europe.”

To applause and cheers from delegates, she confirmed the Scottish government would publish legislation next month setting out the rules for a new referendum.

Sturgeon said last week she wanted it to be held before May 2021. She acknowledged that the UK government had confirmed last week it would refuse to authorise a fresh referendum, but offered delegates no solution to that problem.

In a significant political challenge to pro-UK parties, she announced the SNP would launch its biggest campaign on the economics of independence this summer, including a guide on the subject for all 2.4 million Scottish households, which would need to be delivered by hand.

The SNP also plans to set up a social justice and fairness commission to investigate policies designed to make sure the proceeds from future economic growth are shared out more equally.

Many critics of independence warn it would result in billions of pounds in spending cuts, but Sturgeon insisted the new project would “demonstrate how we can use the powers of independence to end poverty, achieve full employment, and drive equality for all”.

She told delegates: “As an independent nation we will face challenges, as all independent countries do. And we must be responsible with our finances.

“But few countries on earth can match our resources and our potential. So never let anyone tell you that Scotland doesn’t have what it takes to be a prosperous, independent nation.”

Two weekend polls also showed a slight lift in support for independence up to 49% and 47%, excluding don’t knows, taking the SNP much closer to achieving majority support a yes vote. Support for independence jumps to 52% if the UK were to leave the EU with no deal, again excluding “don’t knows”.

She cautioned that the party’s activists still needed to build popular support for independency and demonstrate a tolerant and openhanded way of campaigning that respected the fact many voters were still not persuaded.

“We must always make our case with the decency, respect and dignity that we want to be the hallmark of our independent country,” she said, urging delegates not to divide voters into yes or no voters, but as “fellow citizens who all want the best for ourselves, our families and for Scotland’s future”.