The global population reaching 8 billion people is "not a doomsday scenario" according to United Nations officials, as they call for fast action to reduce fossil fuels and emissions.
A "rapid decoupling" is needed for the world's population to thrive, according to Maria-Francesca Spatolisano from the UN Department of Economic and Social Affairs.
"While it is true slower population growth, if maintained over several decades, will help to mitigate environmental degradation, too often [that growth] is conflated with a rise in greenhouse gas emissions," she said in a UN briefing on Tuesday.
"That ignores the fact that countries with the highest level of consumption and emissions are those where population growth is slower, even negative."
The world's population hit the historic milestone of 8 billion this week, with the UN predicting there will be 9.7 billion humans on Earth in 2050.
Ms Spatolisano said the majority of that growth continued to be concentrated "among the world's poorest countries".
"These countries, which have significantly lower emission rates, are likely to suffer disproportionately from the effects of climate change, in part because they lack the resources needed to adapt.
"In order to usher in a world in which all 8 billion people can thrive, we need a rapid decoupling of economic activity from the current over-reliance on fossil fuel energy, as well as greater efficiency in use of such resources.
"Wealthy countries and the international community [can help] developing countries receive the necessary assistance so their economies can grow.
"[But they should] do so using technologies that will minimise future greenhouse gas emissions."
The UN's 17 'urgent' goals for humanity
Ms Spatolisano also called on countries to "redouble" their efforts to achieve sustainable development goals by 2030.
The UN has 17 Sustainable Development Goals (SDGs) it considers "an urgent call to action" for all countries, including eliminating poverty, hunger and inequality, increasing climate action and creating peace, justice and strong institutions globally.
"As the world faces cascading and interlinked global crises and conflicts, the aspirations set out in the 2030 Agenda for Sustainable Development are in jeopardy," UN secretary-general Antonio Guterres wrote in a 2022 report.
"With the COVID-19 pandemic in its third year, the war in Ukraine is exacerbating food, energy, humanitarian and refugee crises – all against the background of a full-fledged climate emergency."
'A success story, not a doomsday scenario'
The UN Population Fund's (UNFPA) deputy executive director for management, Ib Peterson, said an unprecedented level of diversity between countries was "truly unique".
"We consider this a moment of a success story, not a doomsday scenario," he said.
"The median age in Europe is 41, while the median age in sub-Saharan Africa is 17. So this means people the world over have starkly different needs and starkly different opportunities."
He said the difference between countries would mean solutions needed to be tailored at the local level.
The UNFPA is the UN's sexual and reproductive health agency, aiming to improve reproductive, contraceptive and maternal health around the world.
Asked how governments could help other countries manage their populations and economic growth, Mr Peterson said it was "a clash of different challenges".
"What has worked historically [is to] provide people with choice themselves and the ability to exercise that choice," he said.
"In particular, women and girls, to give them education, to provide them with access to reproductive health services to decide for themselves when and how many kids, and so on.
"That is actually one of the major, major policy moves that need to be taken by governments.
"Then you need to address the other challenges, but that has been shown to have an impact."