As climate-heating fossil fuel emissions continue to rise, renewed efforts to slash them must be fair and take into account countries' other key priorities - such as development in poorer nations - or they will likely fail, scientists warned on Monday.

Emissions will have to be cut swiftly and deeply across economies to limit global warming to internationally agreed temperature limits, they said in a new flagship science report by the Intergovernmental Panel on Climate Change (IPCC).

But "if you do that at the expense of justice, of poverty eradication and the inclusion of people, then you're back at the starting block", said Fatima Denton, one of its 278 authors.

The report's release was delayed by six hours, after governments tasked with approving a key policy summary wrangled over equity, finance and other thorny issues, including how big a role "nature-based solutions" like tree-planting should play in cutting emissions.

The report did not call for the full abandonment of fossil fuels but emphasised that the technology needed to shift to clean energy is largely available and getting ever cheaper.

However, the finance required to deploy it on a large enough scale is still lacking, it added, particularly in poor nations.

Far more than in its previous reports, the IPCC highlighted inequalities in who produces the emissions driving climate change, pointing the finger at the world's richest as having "the highest potential for emissions reductions".

The Russia-Ukraine war, like the COVID-19 pandemic, shows how rapidly countries can make dramatic economic changes to deal with an emergency - something most are not yet doing to lower increasingly clear risks from climate change, said Denton.

"Sometimes it's just about political will - what we're willing to do," said the director of the U.N. University Institute for Natural Resources in Africa.

She questioned the current rush by many wealthy nations to temporarily reopen closed gas and coal facilities to cope with energy shortages brought on by the Ukraine conflict, even as fossil fuel-rich poor countries are exhorted to adopt clean energy.

SOCIALLY ACCEPTABLE

The new IPCC report - focused on ways to cut planet-heating emissions that increasingly endanger lives through impacts from wildfires to floods and droughts - explores social barriers and accelerators of climate action in more depth than past reports.

It warns that the unequal social and economic consequences of emissions-cutting efforts - from affordability to where green jobs are created - can "affect social cohesion and the acceptability of mitigation".

But making sure that a broad range of people - including youth, workers and indigenous groups - are involved in decision-making about a low-carbon transition "can build social trust and deepen and widen support for transformative changes", it noted.

Joyashree Roy, coordinating lead author of a new chapter on the social aspects of mitigation, said efforts to cut emissions needed to pay attention to often overlooked realities - from cultural norms to the human desire for social status.

Policies that ignore the situation on the ground, which varies widely between countries, are unlikely to work, the Indian economist said during an online event.

The report noted emissions-cutting options "that align with prevalent ideas, values and beliefs are more easily adopted and implemented".

Policies to reduce emissions should not be pursued separately from sustainable development efforts, as is too often the case now, Ghana-based Denton told the Thomson Reuters Foundation.

For instance, as many countries grow more crops for biofuel in a bid to hold down emissions, they can undercut agriculture, harming food security, or displace people from their traditional land and rob them of an income, she said.

Denton said many oil-rich poorer countries, including in Africa, still want to develop using the fossil fuels they have and cut emissions later, as richer nations are doing, because they lack the means to grow only with clean energy.

"It's doing it all at once that feels a little too stringent," she said.

POLITICAL PRESSURE

Rachel Kyte, dean of The Fletcher School at Tufts University in the United States, said many people around the world want to make low-carbon shifts in their lives but need help doing it.

"If you deal with the upfront cost of moving from a gas boiler to a heat pump and make it easy to do ... people will do it," she said during an online event.

Michael Grubb, a professor of energy and climate change at University College London and an author of the IPCC report, said cutting emissions had costs but also significant potential to improve lives, something that needed more political emphasis.

The price of zero-carbon electricity, for example, is half to a third of what most people now pay for their power, he noted.

"If that's not an opportunity... in terms of political narrative, I don't know what is," he added, especially as the Ukraine crisis sends gas bills soaring.

"This low-carbon stuff could actually be rather nice," he added - from cleaner cities to quieter cars and cheaper energy.

The reason such changes are not happening faster, he and others said, is not due to a lack of technology or even finance but rather political resistance or social roadblocks.

"A lot of things economists say would make sense haven't happened because of policy and politics," Grubb told an online event.

Robert Brulle, an environmental sociologist at Brown University in the United States, said early drafts of Monday's report had referenced threats to climate action from things like political donations, lobbying and deliberate misinformation.

But those references did not make it into the final version or the summary for policymakers, the most public-facing part of the document, which he called "an enormous disappointment".

"If you read it, you wouldn't know there is a large-scale organised effort to stop action on climate change. You wouldn't know anything about climate misinformation or greenwashing," he said in an interview.

That is a serious problem if the report aims to spur emissions cuts, because "the political and cultural barriers to climate action are one of the major reasons we aren't doing it", he added.

Denton said one answer lies with social movements pushing for a stepped-up response, such as the Fridays for Future student strikes launched by Sweden's Greta Thunberg, which are likely to play a growing role in pressuring governments.

Protesters on the streets could swell as climate disasters hit more people and they start to wonder if governments are doing enough to protect them, Denton predicted.

"What we’re seeing with Greta... is going to continue until the problem is solved or people have faith in where we’re headed," she added.

(Reporting by Laurie Goering @lauriegoering; editing by Megan Rowling. Thomson Reuters Foundation