'Positive' climate tipping points are possible. What are they?

Scientists believe dangerous climate change "tipping points" are approaching - from surging sea levels as polar ice melts to fast-spiking temperatures as methane escapes thawing permafrost.

A study published this month in the journal Science found that four dangerous planetary tipping points are likely if global warming reaches more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial temperatures.

That limit - which governments are striving to keep to under the 2015 Paris Agreement - could be passed within a decade, scientists have warned.

Tipping points happen when a small change - such as an incremental increase in global temperature - sparks a rapid and often irreversible transformation.

But they may not all be bad. "Positive" tipping points for the climate are also possible, as solar and wind power grows cheaper than fossil fuels, electric vehicles take off, meat substitutes become tastier and social norms shift.

"I think our best, and possibly last, hope of avoiding the bad tipping points is finding and triggering some good tipping points," said Tim Lenton, director of the Global Systems Institute at the University of Exeter.

Here's a look at some of the potential positive shifts and ways they might be triggered:

In Norway, 84% of new cars sold in January 2022 were electric, part of an accelerating move away from fossil fuel-run vehicles. It is also happening in other places, if more slowly.

Why is the swap occurring? In Norway, a combination of rising taxes on fossil fuel vehicles and subsidies to buy electric ones has made the latter the cheaper choice.

In a growing number of countries, rising vehicle efficiency standards, investments in charging infrastructure, higher fees on more polluting cars or limits on where they can be driven are all helping more drivers to view electric as the smart next buy.

In industries such as the automotive sector, getting "keystone actors" - including CEOs of major companies - educated about potential climate risks and the profits to be made from an electric switch can also drive change, said Johan Rockström, director of the Potsdam Institute for Climate Impact Research.

The leading climate scientist now sits on an advisory board for Daimler - the parent company of Mercedes-Benz - one of a growing tide of major manufacturers now planning to stop selling fossil fuel vehicles in the 2030s.

Similar green shifts among major corporate players are happening in other sectors, including the seafood industry, he said.

"Business has changed from its focus on corporate social responsibility, which is about perceptions," Rockström said.

"Now it's about a strategy for competitiveness."

Feeding livestock is a massive strain on the world's tightening food supplies and the expansion of farm fields and pastures for fodder is one of the largest global factors behind deforestation, a major contributor to climate change.

While overall meat consumption is rising, as the world's population grows and some poorer nations become more affluent, a surge in tastier and more appealing meat substitutes is helping drive a shift from meat-eating in some countries.

Scarlett Benson, who works on tipping points for the Food and Land Use Coalition, said a faster switch to meat alternatives - like many green shifts - is becoming possible as five "enabling" conditions are increasingly met.

Those include: price (is it cheaper?), performance (does it taste good?), accessibility (can you get it at the local shop?), culture (are your friends and family also doing it?) and capability (do you know how to cook it?).

Other changes accelerating the move away from meat range from investment in innovations - such as lab-grown meat - to use of public procurement - including buying meat substitutes for school lunches - to help create economies of scale, Benson said.

Additional measures could include setting national dietary guidelines, banning marketing of unhealthy products and, eventually, putting in place a carbon tax, she added.

Renewable power - solar and wind - is rapidly becoming the cheapest form of energy in much of the world, a reality that means even those who do not care about climate change are likely to find themselves using it, said Doyne Farmer, director of the complexity economics programme at the Oxford Martin School.

But economic nudges are, in some places, speeding the shift.

Britain, for instance, slashed climate-changing emissions from its electricity supply at eight times the global rate over the last decade by using a small carbon tax that made coal energy uncompetitive with gas, said Simon Sharpe, a senior fellow at the World Resources Institute.

Significant investments in offshore wind power - Britain now has more capacity than any other country - and a pioneering government pledge to become net-zero by 2050 also have driven advances in green electricity.

What can help drive smart decisions, Sharpe said, is a switch from weighing up costs and benefits, often in the short term, to analysing risks and opportunities instead.

That could help speed decarbonisation, will needs to happen five times faster than current levels globally, Lenton said.

"We need some ways of accelerating an agreed-upon change - and creating systems that then self-accelerate is the crux of a positive tipping point," he said.

Social tipping points may also be emerging, from graduates shunning jobs at unsustainable companies to families investing in solar panels, eating less meat or joining climate change protests when friends and neighbours do those same things.

"Tipping happens not because all see the light at once but because we're influenced by opinions of others," said W. Brian Arthur, a California economist who works on complexity theory.

"When a sufficient number change their ideas ... it becomes more likely you'll change your ideas," he said, citing how smoking saw a rapid and swift decline starting in the 1970s as its health impacts became clear and restrictions were enacted.

In almost all cases, politicians act on a problem only once they see there is social backing, he said - one reason taking individual action on climate change matters.

The coronavirus pandemic has shown that societal change - and finance to deal with threats - are possible "at a speed and scale we thought previously unimaginable", said Andrew Simms, founder of the Rapid Transition Alliance, a network of international organisations working to speed up climate action.

Now, he said, it is time to apply that approach to dealing with climate threats, and improving lives in the process.

"What's not to love about insulated homes? Jobs created insulating homes? Investing pensions in renewables? Some of these solutions are in front of us – we just need to roll them out," he added.