Climate crisisWe Climate Scientists Won’t Know Exactly How the Crisis Will Unfold Until it’s Too Late
When we hold on to things for too long, change can come about abruptly and even catastrophically. While this will ring true for many from personal experience, similar things can happen at large scales as well. Indeed, the history of Earth’s climate and ecosystems is punctuated by frequent large-scale disruptive events.
When we hold on to things for too long, change can come about abruptly and even catastrophically. While this will ring true for many from personal experience, similar things can happen at large scales as well. Indeed, the history of Earth’s climate and ecosystems is punctuated by frequent large-scale disruptive events.
When the air warmed and the last ice age was coming to an end, the continent-size glaciers – or ice sheets – stayed around for much longer than the climate would allow. Then parts of them collapsed in spectacular fashion. One such collapse – we still don’t know of which ice sheet – caused at least four meters of sea level rise per century and possibly also the following abrupt transition to a much warmer climate, only to be followed by an equally abrupt flip-flop between warm and cold conditions, before the onset of the stable climate we have enjoyed until recently.
This long period of stability seems to have ended already. Australia’s climate had been warming rapidly for many decades, and eventually the moment came when record-breaking extreme heat coupled with an exceptionally dry period created the conditions for a series of mega fires.
In all, the fires burned more than 20 percent of temperate broadleaf forests in New South Wales and Victoria, compared to less than 2 percent in a typical season. Many of the forests may never recover to their previous state. Other ecosystems may contain similar tipping points.
Predictive models are the lifeblood of climate science, and the foundation upon which political responses to the climate and ecological crisis are often based. But their ability to predict such large-scale disruptive events is severely limited.
For example, the massive scale of the recent Australian bushfires goes beyond what any model used by the Intergovernmental Panel on Climate Change (IPCC) has ever simulated – for the present or the future. In fact, one of us (Wolfgang) has published extensively on future wildfires, and his work found that fire activity in parts of south-eastern Australia would likely increase significantly by the late 21st century. In reality, much more widespread fires occurred some 70 years earlier than predicted.
This isn’t the only case where models used by climate scientists are inadequate. The IPCC’s estimates of how much CO₂we can still emit to be on the safe side explicitly leave out many known large-scale disruptions or tipping points because of insufficient understanding or because models cannot capture them.
