Jellyfish on beaches: A warning cry from a changing climate

Some people believe that jellyfish appearing on beaches are just another nuisance designed to ruin our vacations, much like mosquitoes or ticks. But in reality, their painful stings are screams—not just ours. Nature itself is crying out, as it is being thrown off balance by climate change, which is disrupting the world at a dizzying pace. It is as if the game board, with rules that had remained more or less stable for the last 15,000 years since the end of the last ice age, has been kicked over.

Because—pay attention, deniers—a study published in Science confirms that the major climate changes over the past 2.5 million years were triggered by natural shifts in Earth’s axis of rotation. The current changes, as demonstrated by the Intergovernmental Panel on Climate Change (IPCC), are caused by the accumulation of carbon dioxide in the atmosphere, a result of our reckless consumption of fossil fuels.

What will I read in this article?

• More jellyfish on beaches—and even in the Arctic
• Viruses carried by mosquitoes
• The growing threat of ticks
• Grizzly bears without hibernation
• Hungry polar bears with no ice
• Nature’s cries for change

More jellyfish on beaches—and even in the Arctic

The sight of massive swarms of jellyfish washing up on beaches during the summer is not an isolated event in the Mediterranean. In fact, no sea is immune, whether it is the coasts of the Gulf of Mexico, northeastern Australia, the Atlantic coasts of the Canary Islands, or the shores of Galicia, Asturias, and the Basque Country in northern Spain. And putting up nets to keep jellyfish off beaches, which experts call mere “environmental band-aids,” does little to solve the problem.

With rainfall decreasing and solar radiation increasing, waters are becoming warmer—perfect conditions for these gelatinous, stinging creatures. Heat speeds up their metabolism, and even the frozen Arctic is warming. A recent scientific study estimates that seven out of the eight most common jellyfish species there are shifting their habitats northward in response to climate change.

Viruses carried by mosquitoes

From jellyfish, we now turn to mosquitoes—especially the dangerous tiger mosquito. This invasive species, originally from Asia, has spread across southern Europe in just 20 years. It bites not only during the day but also at night, causing painful reactions. The real threat, however, lies in its ability to transmit viral diseases such as dengue, Zika, and yellow fever.

Their local relatives, common mosquitoes of the Culex genus, have also become a serious threat along Mediterranean coasts. Climate change has triggered their spread, and they have begun transmitting the West Nile virus. A recent study linked the increasingly mild winters to the spread of this disease in southern Spain, proving its connection to global warming.

The proliferation of ticks

Another “bug” that we do not like to have around is the tick. In recent years, populations of these blood-sucking insects, which carry various diseases, have surged across Europe and the Americas. This increase is not just a natural fluctuation; it is directly tied to climate change, which has altered weather patterns and ecosystems, allowing these creatures to thrive.

Rising global temperatures have created milder winters and longer summers—ideal conditions for ticks. In regions such as northern Mexico and much of the United States, especially rural and wooded areas, ticks have expanded into previously unaffected territories. Along with them, cases of serious diseases like Lyme disease, spotted fever, and anaplasmosis have also skyrocketed.

In Mexico, where ticks used to be more common in rural or livestock areas, warming and increased humidity have driven them into more urbanized areas, creating growing concerns for public health.

Sleepless grizzly bears

But the impact of climate change is not only visible in tiny creatures. In the northern U.S., hikers and nature lovers are increasingly worried about changes in grizzly bear hibernation patterns, a phenomenon directly tied to global warming.

Traditionally, these massive animals hibernate for five to seven months, relying on fat stores accumulated during summer and fall. However, global warming has disrupted this cycle, causing many bears to delay, shorten, or even skip hibernation altogether. This has led to more frequent and dangerous encounters with humans, particularly in popular hiking and camping areas in Montana, Wyoming, Washington, and the forests of the Northeast.

Recent studies show that some bears in regions like Yellowstone and Glacier National Park are delaying hibernation by up to a month, while others wake up early due to erratic winter temperatures. Worse still, in areas where it no longer gets cold enough, some bears skip hibernation entirely, staying active through the winter.

No ice and too hungry

Polar bears, iconic symbols of Arctic wildlife, face an unprecedented crisis due to climate change. With ice melting at record speeds, their habitats are shrinking, and food shortages are pushing these predators into increasingly desperate situations. Polar bears are spending more time on land, away from their usual ice-covered hunting grounds.

As a result, they have been forced to venture into human-inhabited areas, sometimes scavenging for food among livestock or even garbage. In remote Arctic communities, encounters between polar bears and humans are becoming more frequent—and more dangerous. This phenomenon is directly linked to global warming.

The cries for change

According to the IPCC’s current global warming projections, it is likely that the spread of jellyfish, mosquitoes, ticks, and the diseases they carry will increase. Grizzly bears will hibernate less, and polar bears will venture closer to human settlements.

By the end of the century, many areas currently free of these problems may face high risks, threatening both wildlife and human populations. This will come with a significant economic toll.

These are the cries of climate change—the signals nature is sending us, urging us to step up efforts to decarbonize the global economy. It is still possible to avoid the worst consequences, but the window of opportunity is rapidly closing, and the problems are only growing.