A planet on the brink: Climate scientist Johan Rockström warns Earth is nearing its limits - NUS

The session, moderated by NUS Vice President (Sustainability & Resilience) Professor Koh Lian Pin, drew over 650 students, academics, policymakers and business leaders who came to hear the insights of the climate expert on the future of the earth.

A planet at its limits

Prof Rockström is well known for leading the development of the planetary boundaries framework, which defines nine critical earth systems— such as climate change, ocean acidification and freshwater change— and the limits within which humanity must operate for a safe and stable planet.

Drawing on decades of data, Prof Rockström described how the Earth entered a period of accelerating instability around 1950, which coincided with the end of the two world wars and the start of the third industrial revolution.

Today, seven of the nine planetary boundaries have been breached, putting the planet under dual strain— the mounting stress of climate change and a weakening capacity to withstand it.

As such, even the complete elimination of fossil fuels would not guarantee safety. “Even if we phase out fossil fuels to a completely fossil-fuel-free world economy in 25 years, we will still fail,” he said. “Because the breaching of the biosphere boundaries will, on their own, push us beyond 1.5 deg C.”

Recent data, he added, show that the planet is already beginning to lose its buffering strength. “The carbon uptake capacity of forests is going down. The Brazilian part of the Amazon Basin has already flipped over and is no longer a carbon sink,” he said. “These are signs of a system that may be moving to a more fragile state.”

Lessons from the past

In response to a question from the floor on what lessons today’s leaders can draw from the 1987 Montreal Protocol, Prof Rockström called that treaty “a remarkable achievement”. The world, he said, had listened to science and acted accordingly by phasing out ozone-depleting chemicals. “Nobody had seen an ozone hole, yet the world trusted science and the conclusion that it was an existential threat.”