Climate Change Is Stranding Hundreds of Dying Baby Sea Lions in California

Last week, as the United States added its support to the first global law that would finally hold nations accountable for climate change, biologists in California were attempting to triage an influx of dying sea lions—victims of global warming—that had washed up on their beaches.

Animal rescuers first witnessed the sudden arrival of hundreds of emaciated pinnipeds in early 2013. The majority of the sea lions were pups, and almost all of them showed signs of viruses and infection, in addition to severe malnourishment. The exact source or pathogen responsible for the unprecedented event wasn't immediately clear.

Scientists at the National Atmospheric and Oceanic Administration (NOAA) agreed that it was an "unusual mortality event."

Since then, these sudden, mass strandings continued every year in the spring.

Historically, the atmospheric phenomenon known as El Niño has caused sea lion numbers to ebb and flow over time. Every so often, a starvation epidemic will level an entire generation of sea lion pups, as uncharacteristically warm waters decimate their food supply.

But 2013 and 2014, while hotter than ever, weren't El Niño seasons, and the pups that washed ashore appeared to have been born sick. Sea lion mothers were barren of life-supporting milk for their offspring, and many were forced to leave their young for days at a time in search of food. Some scientists suggested the ocean stranded the animals because it just couldn't support them anymore.

This year, animal rescue centers have reported record-breaking sea lion numbers at their facilities. Many are already at capacity, such as the Pacific Marine Mammal Center in Laguna Beach where staff are rehabilitating 130 animals at any given time. According to the center, sea lion strandings this year are nearly four times higher than the average from 2003 to 2012.

Researchers and wildlife officials are struggling to keep bystanders away from the sick animals on Malibu's beaches because there are simply too many to keep track of. According to the Marine Mammal Protection Act, no one is allowed within 100 feet of the sea lions, but curiosity and misguided attempts to help the dying pups have resulted in beach-goers unnecessarily stressing them.

The real causes of the epidemic are overfishing and climate change. Together, they deliver a one-two punch to sea lions.

There's now scientific consensus that as greenhouse gasses heat Earth, El Niño will not only intensify, it will appear more frequently, reducing the time that ecosystems need to naturally recover from its effects.

Climate change is also compounding other major threats to sea lion populations, the primary being overfishing of the animal's most important food source. Sardine numbers off California have dropped by 90 percent since 2007, according to a National Marine Fisheries Service assessment. In 2012, NOAA scientists warned of a fatal sardine population collapse, but they never anticipated it would ever lead to a mass sea lion starvation event.

"Sea lions are an indicator species that are showing not all is well in the current California ecosystem. There is simply isn't enough food out there," Geoff Shester, California Program Director at the conservation organization Oceana, told me.

Conservation groups are focused on promoting policies that would curb overfishing and help to replenish sardine and anchovy numbers, he said.

Until we address the root cause of overfishing, sea lion numbers will undoubtedly continue to starve. But as ocean conditions become more extreme, even protected fish populations might never have the chance to recover.

The ripples of climate change are being seen all around the world, but it's not often they wash up on our very doorstep. In a way, the stranded sea lions are an unfortunately opportune mascot for the cascading environmental effects of global warming. Afterall, "baby sea lions are dying" and people care about that.

"You can see the eyes of these creatures that are starving to death," Shester said. "It's a sad occurrence that's happening right now, but it draws a lot of people in."

Thankfully, the sea lion pups have a pretty good recovery rate, and rescue staff are more prepared than ever to rehabilitate them. But once released back into the ocean, will it only spit them out again? Let's hope not.