The climate is changing more quickly now than it has done for tens of millions of years. This was the blunt conclusion to the BBC’s recent Earth series, which sought to convey to viewers how cataclysmic the disruption caused by global heating could be. Chris Packham, its presenter, described the tipping points that were reached 56m years ago, when, over the course of a few thousand years, temperatures climbed by 5C. Fossil records from this period are one resource that modern scientists use when trying to predict the consequences of the much faster heating that is now under way.
Planetary boundaries, about which scientists this week issued an updated warning, are another tool for thinking about the environment. These are a set of parameters defined at the Stockholm Resilience Centre, led by Prof Johan Rockström, in 2009. They are limits within which changes to the earth’s life support systems, which have been relatively stable for 10,000 years, can be considered manageable. Once the boundaries are breached, however, everything becomes much more extreme, unstable and threatening. As well as an attempt at quantifying the disruption that natural systems can withstand, the nine boundaries represented an attempt to broaden understanding of the risks. One key message was that global heating caused by greenhouse gases trapped in the atmosphere is not the only threat.
The latest assessment, that six out of the nine boundaries have been broken, is yet another wake-up call. For the first time, scientists assessed the situation across the whole world and are particularly concerned about their findings with regard to biodiversity, freshwater and land use. Along with phasing out fossil fuels, they argue that ending destructive farming practices – which cause deforestation, habitat loss and pollution on a massive scale – is now the most urgent priority.
Prof Simon Lewis describes the boundaries framework as a “heroic attempt to simplify the world”. As such, it has something in common with Kate Raworth’s doughnut economics. But, however valuable such concepts are, ultimately they will be judged on whether they can help prompt the imposition of actual limits on fossil fuel production, and other damaging activity, that can only be imposed by governments.
The phasing out of coal, oil and gas was dropped from last year’s Cop27 climate summit. This week, Fatih Birol, who heads the International Energy Agency, said that it must be back on the agenda at Cop28, which opens in Dubai in two months. Confidence in the UN climate process was damaged by the appointment of Sultan Al Jaber as this year’s president. He also heads the Abu Dhabi National Oil Company. Currently, the UAE is planning a massive expansion of oil and gas.
But opposition to the UAE’s plans, and those of Saudi Arabia and western oil businesses, is growing. Rishi Sunak is expected to miss a climate ambition summit hosted by the UN secretary general, António Guterres, next week. His enthusiasm for new oil and gas investments may have disqualified him from attending. But other leaders will be urged to seize the chance to set the world on a path to a transformed energy system. With evidence of the suffering caused by global heating continuing to accumulate, alongside alarming assessments from experts, the need for governments to formally acknowledge the planet’s boundaries, and act accordingly, has never been greater.