There are now 8 billion people. What does that mean for the world?

The UN estimates the global population to have surpassed 8 billion people on Monday. EPA

Tuesday was a remarkable day for humanity. The global population is estimated to have passed 8 billion people.

It was only in 2011 that the number reached 7 billion. To put that blistering rate of growth into perspective, it took 123 years, from 1804 to 1927, for the global population to increase from 1 to 2 billion.

The official UN announcement about the 8-billion mark was made at the Cop27 climate summit, which is currently taking place in Egypt. Some will have viewed the timing as both ominous and symbolic. Humanmade factors are, after all, contributors to the climate crisis, and there are fears among some activist groups that an increase in population inadvertently poses a greater threat to the planet.

But the UN was keen to stress that passing the 8 billion milestone was hardly an inauspicious moment. John Wilmoth at the UN Department of Economic and Social Affairs was more optimistic, saying that a large population is a "reflection of our success as a species," although he did go on to say that the news raises "questions" about our impact on the planet.

In the most basic terms, a large population is a sign of health. The UN says longer lifespans is a key reason for today's rate of growth, particularly in developing nations. This points to rising living standards across the board, and a global economy in which more and more people can take part and earn a sustainable living.

India's population is soon expected to overtake China's, making it the most populous country globally. AP

It is also worth noting that while population is expected to rise for about the next 60 years, fertility rates worldwide have mostly been dropping since 1950, when women on average had five children, more than double today's average, 2.3.

Advanced economies are disproportionately driving this downturn. Regions that buck the trend are most often in poorer parts of the world. The region with the highest birth rate is, for example, Central Africa, home to many of the world’s lowest-GDP-per-capita nations.

The Middle East is a mixed picture. Iran's birth rate has tumbled since the late 1980s, whereas Egypt's actually started to rise after 2006, only to start very gradually declining 10 years later.

Nonetheless, the UN lists Egypt as one of a group of eight countries that are projected to constitute half of the global population growth by 2050, the others being the Democratic Republic of the Congo, Ethiopia, India, Nigeria, Pakistan, the Philippines and Tanzania.

This seismic trend must be factored into future climate strategies. Developing countries will have to strike a complex balance between growing their economies to provide ample jobs for larger populations, with responsibilities towards protecting the planet.

It would, however, be wrong to pin the blame of climate change on these nations. After all, it is the world’s richest people – with larger carbon footprints, more consumption and less-sustainable lifestyles – who disproportionately contribute to greenhouse gas emissions. The poor tend to pay the highest and earliest price, living in countries with less money to help them and more often relying on nature for a living.

The world population is estimated to increase by another billion some time in the early 2040s. That is an important window to carry on preparing for a growing world.

There have been successes in this regard during the past 11 years. Medical science continues to advance, technology provides more equitable access to jobs across the world and countries are committing to ambitious climate targets in the hope that action now can protect us from climate change. This work must never stop. Billions of lives to come rely on it.