Climate Week has come and gone this year, largely swamped in the news by social and political crises big and small. Commemorations like these are ostensibly about remembering and raising awareness around Mother Nature, but unfortunately we’re fast approaching a time when people in the United States and around the world are not really going to be able to forget about the climate, pretty much anywhere and any time. It’ll range from relatively small reminders, like feeling that you need to keep your A/C running into late September, to the devastating, unavoidable ones, like Hurricane Helene, which is currently ravaging the Southeast. Inevitably, there will be those who try to hand-wave all this away, pointing out that this is about hurricane season and we’ve always had hurricanes that have always done damage. We wish we could ignore these people, who seem committed to nothing beyond a kind of reflexive contrarianism, but they, too, can do a lot of damage if left unchecked. Helene is the first recorded Category 4 hurricane to hit Florida’s Big Bend region, a behemoth of unusual ferocity that is driven in part, inarguably, by changes to the climate that was unleashed by humans. It’s already killed dozens of people and caused record flooding well inland, in several states. We won’t know the full extent of the destruction until later on, as the storm has knocked out communications, but unfortunately we can expect the death toll to rise and the damage to compound. This is a particularly overt and immediate disaster, but others will be more subtle or slower-moving. Rising temperatures will push mosquito latitudes down and increase their breeding periods, leading to more mosquito-borne disease in places where they haven’t typically arisen in large numbers. Water might be saturating the Southeast right now where it’s unwelcome, but other areas will run dry, with freshwater scarce and the crops and people there suffering. Even the heat itself will strain energy and infrastructure systems and pose acute threats to the life and health of residents that cannot get a respite, such as the people of Phoenix, who are experiencing several days straight of record-breaking heat, reaching 108 degrees a few days before October. These are exactly the kinds of consequences that were long predicted, that climate scientists and advocates have been sounding the alarm about for decades, and which were so often dismissed as fear-mongering. Human optimism has been the key to our survival, but also sometimes leads us to tune out the blaring alarm bills with the sunny belief that things will be alright. Yet fatalism, too, is toxic. The reason we observe Climate Week isn’t because we have now given up; it’s not a memorial but a call to action. Yes, we’ve waited too long to head off all impacts from climate change but we can still act to head off the worst of it, though not if we throw up our hands. It will take leaders not just here, but around the world, especially in countries now most responsible for climate-altering pollution, like China, to act with nearly unprecedented coordination and common purpose, which means that the public must demand it. It might seem like an enormous task, but the alternative is far worse.