(CNN) Nearly two-thirds of respondents believe that climate change is a "global emergency," according to a survey of 1.2 million people in dozens of countries around the globe -- and many want urgent action to tackle the problem.
The United Nations Development Programme (UNDP), which ran the poll with Oxford University, described it as the largest survey of public opinion on climate change ever conducted. Unusually, it captured the views of more than half a million people under the age of 18, a key but typically hard-to-reach constituency, the organization said.
The "Peoples' Climate Vote" was undertaken late last year in 50 high, middle and low income countries that together account for more than half of the world's population over the age of 14, according to the UNDP report.
Across those countries, 64% of people said climate change was an emergency, "presenting a clear and convincing call for decision-makers to step up on ambition," the report said.
"Of the people that said climate change is a global emergency, 59% said that the world should do everything necessary and urgently in response," it added. A further 20% backed acting slowly, while 10% thought the world was already doing enough.
While younger people showed the greatest concern over climate change, with 69% of those aged 14-17 saying there is a climate emergency, around two-thirds of those aged 18 to 59 and 58% of those aged 60 and over agreed. This illustrates "how widely held this view has become," the UNDP said.
Its polling also indicated that majorities backed climate action even when it would have a significant impact on their own country, at a time when much of the world is reeling from the effects of the coronavirus pandemic.
Respondents were asked where they would most like to see action, with questions on support for 18 policy options across six areas -- energy, economy, transportation, farms and food, protecting people, and nature.
Four climate policies emerged as the most popular globally, with 54% of those surveyed favoring conservation of forests and land, 53% choosing increased use of renewable energy, 52% supporting climate-friendly farming techniques and 50% wanting more investment in green businesses and jobs. The promotion of plant-based diets was the least popular, with only 30% support.
There were "clear calls" for renewable energy even in higher emitting countries such as the United States, Australia and Canada, the UNDP report said.
It also found "strong backing" for action to conserve forests and land in countries with high emissions from deforestation and land-use change, such as Brazil, Indonesia and Argentina.
"The results of the survey clearly illustrate that urgent climate action has broad support amongst people around the globe, across nationalities, age, gender and education level," Achim Steiner, UNDP administrator, said in a news release.
"From climate-friendly farming to protecting nature, and investing in a green recovery from Covid-19, the survey brings the voice of the people to the forefront of the climate debate. It signals ways in which countries can move forward with public support as we work together to tackle this enormous challenge," he said.
The publication of the survey comes as many countries are preparing for the 26th United Nations Climate Change Conference (also known as COP26) in Glasgow, Scotland, in November.
In the United States, President Joe Biden has put action to combat climate change high on his agenda. He is expected to sign several executive actions related to climate on Wednesday, including issuing a moratorium on new oil and gas leases on federal lands, according to a person familiar with his plans.
This follows on from a series of steps last week aimed at reprioritizing environmental issues. Biden halted more than 100 regulatory actions taken by the Trump administration, announced the US would rejoin the Paris climate agreement and canceled the Keystone XL pipeline.
The UNDP poll was undertaken as part of a wider UN campaign to educate people about climate change solutions and ask their opinions on actions to address the climate crisis.
Global average temperatures last year were tied for the hottest on record, capping what was also the planet's hottest decade ever recorded, according to data analysis released earlier this month. The last six years are now the hottest six on record, with 2020 on par with 2016 as the hottest year ever recorded.
The highest level of public belief in the climate emergency, at 74%, was found in people living in small island developing states, the UNDP report said, followed by people in high income countries (72%). It stood at 62% in middle income countries, while the least developed countries saw the lowest level of support, at 58%.
A majority across all regions said climate change was a global emergency, with the highest level of agreement in Western Europe and North America, at 72%, and the lowest in Sub-Saharan Africa, at 61%.
The UNDP poll sought to reach people under the age of 18 by distributing its questions through adverts in game apps on mobile phones. This "new and unconventional approach to polling" allowed its authors to reach "a huge, unique, and random sample of people of all genders, ages, and educational backgrounds," the UNDP said.
The poll found that the more education a person had completed, the more likely they were to think there was a climate emergency, regardless of where they lived.
"With the onset of the Covid-19 crisis, the Peoples' Climate Vote took on added meaning by providing insight into perceptions about the climate crisis in the context of a global pandemic," the report said.
"Many of the policy choices in the Peoples' Climate Vote -- whether relating to jobs, energy, protecting nature or company regulation -- speak to issues that countries are facing as they chart their recoveries."
Correction: An earlier version of this story incorrectly stated the public level of belief in the climate emergency as the level of support for climate action. It also included a graphic that mischaracterized the United Nations Development Programme survey's methodology. The story has been corrected and the graphic has been removed. The story has also been updated to clarify the surveyed population's age range.