Two explosions were reported on Aug. 31 at the flood-hit Arkema plant in Crosby, Tex. (Reuters)

Among Hurricane Harvey’s devastating effects were environmental accidents. In Crosby, Tex., for example, a chemical plant lost electrical power, leading to a massive fire. While media reports have understandably focused on the flooding, these accidents reveal a new consequence of climate change — some of which will prompt fierce political fights over who should pay for the cleanup. With Hurricane Irma barreling down on Florida, more such fights seem likely.

Was Harvey — and the environmental accidents that resulted — caused by climate change?

Hurricane Harvey reached Category 4 at its peak. Although it was downgraded to a tropical storm by the time it did most of its damage in Texas, there it dropped an unprecedented 35 inches of rain over Houston in only four days. Scientists are careful to say that it is impossible to pin any single event, like Harvey, on climate change. After all, hurricanes were happening long before the global climate started to change in the 20th century.

Still, there is good reason to think that climate change contributed to Hurricane Harvey’s force. Harvey’s direct environmental impact included wind, rain, and flooding that have been blamed for at least 60 deaths so far.

But the storm also had indirect environmental consequences. After flooding knocked out the emergency backup power for the Arkema chemical plant in Crosby, 19.5 tons of volatile chemicals were no longer getting the refrigeration they needed to avoid combustion. Although EPA officials insisted that no toxic chemicals were being spread, local officials urged residents in a 1.5-mile radius around the plant to evacuate.

The Arkema plant wasn’t the only one. Harvey released over a million pounds of extra air pollutants across the Texas Gulf Coast. Further, the Associated Press reported that 13 Superfund sites (named after the federal fund to pay to mitigate these sites’ industrial pollution) were flooded and possibly leaking pollutants; no EPA officials were immediately on site. Naturally, locals worry about potential effects on their health.

A fire burns at the flooded plant of French chemicals maker Arkema SA after Tropical Storm Harvey passed in Crosby, Tex. (KPRC)

These are knock-on effects of climate change. What does that mean?

Indirect environmental consequences are known as “knock-on effects” or “cue ball effects” of climate change. That’s because in billiards, the cue ball is put in motion first, before hitting other balls to put them in motion. Here the cue ball would be the changes in temperature, precipitation, sea levels, and storm activity that make up climate change itself. Knock-on effects often involve the interaction between climate change and human-made infrastructure or wastes, though they can involve purely natural phenomena, like naturally occurring anthrax buried in — and released from — melting permafrost.

Climate change can cause or exacerbate natural disasters, which in turn create knock-on effects like the chemical plant fire in Crosby. But knock-on effects are also starting to appear even without natural disasters, in places around the globe that are already being affected by the warming climate.

Many military bases, both abandoned and current, will see dangerous effects from climate change

Last year I studied some fascinating but disturbing knock-on effects in Greenland with a team of climatologists. Between 1953 and 1967, the U.S. Army maintained secret bases in Greenland as precursors for a larger ballistic missile complex. The plan, known as “Project Iceworm,” was to deploy up to 600 nuclear ballistic missiles, constantly moving around a 4,000-kilometer (about 2,500-mile) long railway cut into the ice sheet. The bases were eventually abandoned with minimal decommissioning, leaving large quantities of wastes buried in the ice sheet. Those included tens of thousands of liters of diesel fuel, a substantial quantity of polychlorinated biphenyls (PCBs), and even some low-level radioactive waste. Climate change is poised to remobilize these pollutants into the surface water, creating a risk that they will spread and enter the food chain in the nearest human settlements.

In new research, I show that this could soon be a problem for other military bases worldwide. The United States alone has hundreds of overseas bases that require continuous political coordination with host governments over such issues as who gets the lucrative service contracts associated with the bases or how to handle lawbreaking by U.S. personnel.

If these bases also leave behind potential environmental problems triggered by climate change, host governments could be left with a liability for which the United States hasn’t necessarily agreed to pay. Such unfunded liabilities would almost certainly set off complex conflicts — within the host nation, between the host nation and the United States, and among nations in the region. That would raise the political and economic costs of overseas bases — and, in extreme circumstances, could rupture the international relationship under which such bases operate.

Consider former U.S. military bases currently or once situated on islands in the Pacific Ocean. Many of these low-lying islands are harmed by rising sea levels. Not only does the rising sea shrink the landmass on an average day, but the islands are becoming much more vulnerable to overwash during storms.

After World War II and the Cold War, the U.S. military left tons of abandoned toxic waste and even radioactive materials on these islands. For instance, nuclear weapons tests took place in the low-lying Marshall Islands, leaving behind radioactive waste that could reenter the ocean and affect the nearby human population by working its way up the food chain through sea plants and fish. Who is responsible for preventing such toxic effects?

The politics of these ‘knock-on effects’ will probably be messy

We don’t yet know the potential consequences of all these knock-on effects. Scientists are just beginning to assess the risks, the timeline before human health is at risk, and the costs of remediation. Already, however, we can see fights emerging over who will pay.

While the responsibility for climate change itself is global and involves emissions from everywhere, knock-on effects tend to be territorially specific. As a result, some entity — or several entities — have political jurisdiction over the problem. That will prompt fights over who will be responsible for the mess.

For instance, Greenland’s parliament debated the Project Iceworm pollution; it formally asked both Denmark and the United States, which is responsible for the pollution, and it filed a complaint on the issue at the United Nations. In 2016, Greenland’s foreign minister, Vittus Qujaukitsoq, actually accused his Danish counterpart of lying on the issue. Earlier this year, Greenland’s prime minister fired Qujaukitsoq when they disagreed about the forceful approach Qujaukitsoq was taking with Denmark and the United States.

We can expect more such battles as climate change speeds up.

Jeff Colgan is the Richard Holbrooke Associate Professor at Brown University and a Bridging the Gap Policy Engagement Fellow. Follow him on Twitter @JeffDColgan.