Earlier this month, the world gasped at videos of ISIS militants wreaking havoc on culturally important artifacts, mosques, and shrines in Iraq. At the Mosul Museum, militants filmed themselves destroying what they consider idolatrous statues with sledgehammers and drills. A few days later, militants bulldozed Nimrud, a site listed by UNESCO as a tentative World Heritage site for its regal “lamassu” statues. Founded in the thirteenth century B.C., Nimrud was considered the second capital of the Assyrian Empire. 

“These extremists are trying to destroy the entire cultural heritage of the region in an attempt to wipe the slate clean and rewrite history in their own brutal image,” George C. Papagiannis, a past UNESCO World Heritage officer for Iraq, told The New York Times. Others have called the destruction of historic cultural sites a war crime.

UNESCO defines World Heritage sites as places of “cultural and natural heritage around the world considered to be of outstanding value to humanity.” In other words, they're repositories and fonts of human identity, worthy of preservation for future generations. UNESCO sites must meet at least one of 10 criteria to be considered a World Heritage site; those sites can be natural or man-made (or both). Under this definition, ISIS's attacks on cultural sites are no less monstrous. But their flamboyance may overshadow our shared complicity in a far larger threat to human heritage: unchecked climate change. Destruction by hammer-swinging goons is a pittance beside the calamity promised by a few more degrees Celcius.

Just last year, UNESCO published a guide for protecting World Heritage sites from the effects of climate change. And in a paper published today in Science, a team of researchers found that Australia’s Great Barrier Reef, Spain’s Doñana wetlands, and the Amazon rainforest all could collapse. The scientists urge sustained local action. 

“World Heritage sites, like all natural resources, are continually at risk from budget cuts, loss of monitoring programs, or development schemes,” Stephen Carpenter, one of the paper’s co-authors, said in an email. “No system of conservation can be left on autopilot. Eternal observation, adjustment, and learning is essential for maintaining any protected area.”

The study notes that many ecosystems work within the boundaries of a “safe operating space.” Changes in the environment due to climate change can push an ecosystem slightly closer to these boundaries, or nearer an irreversible collapse. Poor local environmental practices—such as overfishing or logging—exacerbate the effects of climate change; the ecosystem moves closer to the boundaries of collapse. Improving local practices, the study finds, can make sites more resilient.

The World Heritage sites mentioned in the study are more than just culturally significant—they're vital to the global ecosystem. “The World Heritage sites have great cultural values that will be lost if the sites change dramatically,” Carpenter said. “[But] in many cases we also lose ecosystem services that have worldwide value.” Carpenter noted that the Amazon rainforest, for one, is essential to the global carbon cycle. The Doñana wetlands, considered by UNESCO as under “very high threat,” constitute one of the largest waterfowl wintering sites in Europe.

The responsibility improving environments for such ecosystems rests directly with national governments. “No country can afford to be complacent,” Carpenter said. Many countries with endangered World Heritage sites, such as Australia and Spain, have the resources to make local changes and to preserve their cultural history. Others, such as Iraq and Vanuatu—a Pacific island nation recently demolished by Cyclone Pam—have had their cultural heritages irreparably damaged. Our outrage at vandals' attacks on our shared human history should not obscure the even greater dangers posed by warming oceans.