Thirty years ago, the world’s nations agreed to prevent dangerous human interference with the climate system. But what is “dangerous climate change”? Just turn on the television, read the headlines of the morning paper or view your social media feeds. For we are watching it play out in real time this summer, more profoundly than ever before, in the form of unprecedented floods, heatwaves and wildfires. Now we know what dangerous climate change looks like. As has been said of obscenity, we know it when we see it. We’re seeing it – and it is obscene.
Scorching temperatures persist across Europe, North America and Asia, as wildfires rage from Canada to Greece. The heat is as relentless as it is intense. For example, Phoenix, Arizona, has broken its record of 18 consecutive days above 110F (43.3C). Even the nights, generally relied upon as a chance to recover from the blistering days, now offer little relief: for more than a week, night-time temperatures in Phoenix have exceeded 90F (32.2C). Meanwhile, severe and deadly flooding has stricken South Korea, Japan, and the north-east United States, from Pennsylvania to Vermont.
The climate crisis – and yes, it is now a crisis – is endangering us now, where we live. Whether it’s the recurrent episodes of hazardous air quality in the east coast cities some of us call home from windblown Canadian wildfire smoke or the toll sadly now being measured in human lives from deadly nearby floods, we are witnessing the devastating and dangerous consequences of unabated human-caused warming. That is a fact.
Indeed, as you “doomscroll” on whatever social media platform you prefer these days, you might see selective images and graphs that would lead you to think Earth’s climate is spinning out of control, in a runaway feedback loop of irreversible tipping points leading us down an inescapable planetary death spiral.
But that’s not what’s happening.
The average warming of the planet – including the most up-to-date measurements for 2023 – is entirely consistent with what climate modelers warned decades ago would happen if we continued with the business-as-usual burning of fossil fuels. Yes, there are alarming data coming in, from record-shattering loss of winter sea ice in the southern hemisphere to off-the-charts warmth in the North Atlantic with hot tub-grade waters off the Florida coast. We’ve also seen the hottest week on record for the planet as a whole this month. We can attribute blame to a combination of ongoing human-caused warming, an incipient major El Niño event and the vagaries of natural variability.
These episodes are a reminder that we can not only expect to see records broken, but shattered, if we continue burning fossil fuels and heating up the planet.
And one of the areas where observed trends truly are exceeding the predictions of climate models is in those extreme weather events we are seeing this summer. One of us has been involved in research that suggests that climate models are still not capturing some of the more subtle physical mechanisms behind persistent summer weather extremes. As the Arctic warms faster than lower latitudes, the temperature difference between the poles and tropics decreases and the jet stream – which is driven by that difference – weakens. Under certain conditions that can lead to a slow, wiggly jet stream, with amplified weather systems that get stuck in place. When weather systems stall like this, the same regions get baked or rained on day after day – precisely the sort of persistent, extreme weather events we’re experiencing this summer.
The incessant parade of heat domes, floods and tornado outbreaks this summer seems to suggest a precarious if not downright apocalyptic “new abnormal” that we now find ourselves in. And it understandably feeds the fearful impression that we’ve exceeded some sort of breaking point in our climate.
How do we reconcile that impression with the picture that emerges from the steady, rather than erratic, warming response we see in both the observations and models? The answer is that the behavior of Earth’s climate system represents a tussle between sometimes opposing mechanisms that alternatively favor stability and fragility. That constant tussle is evident in an examination of Earth’s past climate history. If the system is pushed, it responds steadily – to a point. Push too hard, however, and we risk crossing certain “tipping points”, such as the disintegration of the ice sheets and the massive sea level rise that will ultimately follow.
The only way to avoid crossing these tipping points is to stop heating up the planet. And comprehensive Earth system models show that if we stop adding carbon pollution, the warming of Earth’s surface stops soon thereafter.
So that brings us back to where we started. Yes, we have failed to prevent dangerous climate change. It is here. What remains to be seen is just how bad we’re willing to let it get. A window of opportunity remains for averting a catastrophic 1.5C/2.7F warming of the planet, beyond which we’ll see far worse consequences than anything we’ve seen so far. But that window is closing and we’re not making enough progress.
We cannot afford to give in to despair. Better to channel our energy into action, as there’s so much work to be done to prevent this crisis from escalating into a catastrophe. If the extremes of this summer fill you with fears of imminent and inevitable climate collapse, remember, it’s not game over. It’s game on.