There are planetary boundaries that should not be crossed otherwise the Earth's functions tip and go into overdrive, creating inhospitable conditions for humans. This is the conclusion of some of the world's most eminent scientists who gathered for two days at Tallberg in Sweden last week, at which I had the chance to join their deliberation. Indeed, there is evidence tipping has already occurred in the case of global warming arising from the burning of fossil fuels, as the Arctic sea ice is showing signs of melting much faster than expected.
The warming of the planet will lead to not only rising sea levels but also climatic changes all around the globe affecting temperatures, rainfall, and the frequency and magnitude of storms, floods and droughts, which will affect food production and create many other threats such as disease and displacement.
To fix the problem, humans must reduce emissions of greenhouse gases that warm the atmosphere. This means we have to burn much less fossil fuel: coal, oil and gas. The Kyoto Protocol, a multilateral treaty, was designed to reduce greenhouse gas emissions to avert 'dangerous' climate change. The world's governments are in the process of renegotiating the agreement and it is recognised that substantial reductions are necessary. The question is just how much is needed.
So far, reduction levels are based on how much humans can bear in light of existing economic and social structures. The Stern Review, a report commissioned by the British government and published in 2006, set the range at between 450 to 550 parts per million (ppm) of greenhouse gas concentration in the atmosphere, and Lord Stern, a noted economist, is in the process of tightening the level. However, scientific evidence now shows the upper boundary of what the planet can bear is just 350 ppm. This is why there is now a growing effort to bring the most updated scientific insights to the world's governments for a new climate change treaty.
If we were to use the planets' limits of tolerance as a base for deliberation and negotiation, it should bring a very different set of results than if we continued to base it on what politicians can live with and their perceptions on what industries and vested interests can bear. The planet is in fact not a willing negotiating partner. Exceeding nature's physical boundaries will only threaten the survival of humans and other species.
Greenhouse gas concentration is already at 385 ppm and set for 560 ppm before the end of this century. Scientists fear that if sharp reductions are not made soon enough, it will only lead to faster tipping of boundaries, in particular oceans becoming more acidic as they absorb more greenhouse gases, which kill corals and other sea life. Overfishing for human consumption exacerbates the threat to marine ecosystems.