The World Economic Forum has released its Global Risks Report 2019 ^[1] to coincide with its annual meeting taking place this week in Davos, Switzerland. For the third year in a row, climate change and climate change–related risks dominate the list, accounting for five of the top 10 by both likelihood and impact.

The risks, which are drawn from the views of the WEF’s global network of leaders in business, civil society and government, included the failure of climate-change mitigation and adaptation, extreme weather events, natural disasters, biodiversity loss and water crises. Food insecurity and large-scale involuntary migration also ranked highly.

The rankings shouldn’t be surprising. Greenhouse gas concentrations have continued to increase. The past four years have been the hottest on record ^[2], and the 20 hottest years on record have occurred in the past 22 years. And 2018 was another year of record-setting fires, floods, droughts and storms. The California wildfires were the largest and deadliest ever and record-breaking temperatures and drought across the northern hemisphere summer triggered the worst wildfires in Sweden’s modern history. Unprecedented rains in Japan and South Asia caused deadly flooding, and superstorms, such as Hurricane Michael, caused enormous damage.

2018 also ended with a bang here in Australia. The severe ongoing drought on the east coast contributed to the outbreak of more than 100 bushfires in Queensland, followed and exacerbated by an extreme heatwave, with temperatures in the 40s that smashed records for the month of November. Fire conditions in parts of Queensland were classified as ‘catastrophic ^[3]’ for the first time since the rating scale was developed in 2009 (although experts observed that no bushfire in the state since 1966, when warnings were first introduced, would have been considered as dangerous). Tens of thousands of square kilometres of bush and farmland were destroyed.

Just days later, Tropical Cyclone Owen approached the Queensland coast, threatening significant flooding and raising the risk of severe mudslides from the charred hillsides. Owen set an Australian record ^[4] in dumping 681 millimetres of rain in just 24 hours—more than Melbourne usually receives in a year.

Climate scientists warn that these and other events are the early indications of far worse to come. In a major, authoritative and widely publicised scientific study ^[5] released late last year, the Intergovernmental Panel on Climate Change noted that even a 0.5°C increase in warming (from 1.5°C to 2.0°C above pre-industrial levels) would have unprecedented global consequences in many of the areas of risk identified in the WEF report.

The impacts include the complete collapse of coral reef systems in all of the world’s tropical and sub-tropical oceans; several hundred million additional people falling into poverty; a 50% increase in the proportion of the global population experiencing water stress; 420 million more people frequently exposed to extreme heatwaves; 184 to 270 million more people exposed to an increase in water scarcity; and a 10-fold increase (from 8 to 81 million) in the number of vulnerable people affected by changes to crop yields (jumping to a 50-fold increase at 3°C of warming).

One disappointing aspect of the WEF report’s analysis is the huge disconnect between these environmental changes, the effects of which we are already feeling, and the immediacy of the risks. For example, the section titled ‘Short-term risk outlook’ overlooks climate change, focusing instead on factors such as economic friction between major powers and the erosion of multilateral trading rules. This is the tragedy of our climate change predicament: we seem only able to think of climate change as a distant problem, rather than as a crisis requiring urgent action.

This in part stems from a failure to appreciate the inertia in the climate system. Even if tomorrow we could somehow halt all greenhouse-gas emissions, the climate would continue to warm—irreversibly—for decades from earlier emissions released into the atmosphere. In this respect, the window of opportunity to head off climate tipping points ^[6] and other devastating consequences is rapidly closing. Unlike the short-term risks identified in the WEF report, which can be managed and resolved even after they arise, only immediate and concerted action can prevent the global risk of climate change from becoming a deadly certainty.

A second, related reason for the complacency may be the assumption that climate-change impacts will continue to increase in the future at the same pace as in the recent past. However, the IPCC study demonstrates that this is not the case. It is more accurate to expect the impacts to increase exponentially, rather than linearly. We will be surprised not only by the scale of the impacts, but also by the rapid pace at which they begin appearing. Recent analysis ^[7] suggests that rising greenhouse-gas emissions, natural climate cycles and other factors will combine over the next two decades to make climate change hit us faster and more furiously than previously realised.

The inertia in the climate system and the rapid pace and growing scale of climate-change impacts suggest that countries need to dramatically step up their adaptation and disaster risk reduction efforts. Ultimately, though, the risk of global climate change can be addressed only by a concerted global effort to greatly accelerate the transition from fossil fuels to renewables.