Sir David Attenborough, who has educated so many of us about the wonders of the natural world, presented a very pessimistic view of humanity's future to the media last week. His gloomy outlook was based around two increasingly frequently-voiced concerns: firstly, that increasing global population is going to make life on our planet a lot worse, and secondly, that our “ability to rear 90-95% of babies born” has brought us outside the influence of natural selection, and effectively brought a halt to human evolution. The latter is a complex issue deserving of a blog of its own, but here I'll discuss the former claim. Is Attenborough right to be so pessimistic about a Malthusian explosion that leaves the world crowded, unhealthy, and bereft of wonders?

Our current population is estimated at 7.2 billion, and is predicted to rise to 9-10 billion by mid-century. However, some estimates put this at a peak, with a decline expected afterwards. What could reverse the trend?

There is a well-documented shift in population trends as countries become more developed. While there is an initial population increase as factors such as infant mortality decline, while large families remain the norm, this gradually changes in a more sustainable direction. Indeed, while Britain's population shot up following the industrial revolution, birth rates in the UK and western Europe have now declined to replacement level or below. Education and empowerment of women is a factor; it appears that as women gain more control over their lives and situations, they choose to have fewer children.

It's also near-sighted to assume that our planet will not be able to sustain the current, or even an increased, population. As discussed by the Future of Humanity Institute's Toby Ord in the Oxford Martin School's 'Is the Planet Full?' series, (and also this recent NY Times article), more efficient use of our natural resources like clean water, as well as advances in food production and renewable energy, could allow the planet to provide comfortably for a greater population (with all the benefits that more people could bring) – as long as we can adapt away from a Western-style resource footprint.

The challenges of the 21st Century, as recognised by James Martin and reflected in the Oxford Martin School's research programmes, are clear: we must make a commitment to global equality, particularly in improving the lot of developing nations – doing so will help humanity as a whole. We must also focus research efforts on developing cheap, clean, renewable energy, and on improving the planet's ability to provide for its population in a sustainable manner. And we are already making strides: cheaper organic solar cells and thin-root plants engineered to grow in arid climates are just two examples of directions that could play key roles.

As James Martin put it, humanity is at a crossroads: without the proper foresight and efforts now, Attenborough's pessimism may indeed be proven correct.

But it need not be - and it's this goal that motivates my colleagues, as well as countless other scientists and non-scientists worldwide, to come in to work on rainy Monday mornings.

This opinion piece reflects the views of the author, and does not necessarily reflect the position of the Oxford Martin School or the University of Oxford. Any errors or omissions are those of the author.