Category: Biodiversity

Warming Seas and Microplastics Are Harming Sardines—And Us

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Infographic showing how feeding behavior and temperature affect plastic fibre ingestion in European sardines (Sardina pilchardus). Sardines that use filter-feeding ingest more plastic fibres, expel them faster, and have a lower condition index compared to particulate-feeding sardines. Warmer temperatures (19°C) increase plastic fibre ingestion and speed up intestinal transit time.


Feeding behavior and warming seas influence plastic fibre ingestion in sardines. Sardines that filter-feed ingest significantly more plastic fibres than those that eat larger particles (particulate-feeding). Warmer water temperatures (19°C) lead to faster digestion but also more plastic consumption. Filter-feeding sardines show lower health scores, highlighting the combined stress of microplastic pollution and climate change. (Source: Rodriguez-Romeu et al., 2024)

Sardines may be small, but they play a big role in the ocean—and on our dinner plates. These little fish are a key food source for larger marine animals like dolphins and tuna, and millions of people around the world eat them, too. They’re also packed with nutrients and are considered one of the most sustainable seafood choices out there.

But sardines are in trouble. In the Mediterranean Sea, their population has dropped sharply in recent decades. And scientists are discovering that two major forces—warming ocean temperatures and plastic pollution—are teaming up to make life even harder for these essential fish.

What’s harming sardines may be a warning sign for us all.

The Hidden Threat: Plastic Fibres in the Ocean

Microplastics are tiny pieces of plastic that break down from larger items like bottles, bags, and packaging. But not all microplastics are the same. A specific type called plastic fibres is even more common in the ocean—and more likely to be eaten by fish.

Plastic fibres are tiny thread-like pieces that come from clothing, fishing gear, and other waste. They’re too small to see with the naked eye but can float in the water, where fish easily mistake them for food. In fact, up to 91% of microplastics in ocean water are fibres, making them the most common type of plastic pollution in the sea.

The Experiment: What Scientists Found

To better understand how sardines interact with plastic fibres, scientists designed a unique experiment. They took wild sardines and placed them in tanks that mimicked ocean conditions. The tanks contained a realistic amount of plastic fibres—five fibres per liter of water, similar to what’s found in polluted areas of the sea.

They fed the sardines in two different ways:

  • Particulate-feeding: Fish were given large food pellets, which they eat one by one.

  • Filter-feeding: Fish were given tiny particles, similar to how they naturally eat plankton by filtering water through their gills.

The scientists also tested two water temperatures:

  • 16°C, which reflects current Mediterranean conditions.

  • 19°C, which represents a possible future scenario as oceans warm due to climate change.

Startling Results: What Happened to the Sardines

The results were clear—and concerning.

Sardines that fed by filter-feeding accidentally ate about eight times more plastic fibres than those eating larger particles. On average:

  • Filter-feeders ingested 4.95 fibres per fish

  • Particulate-feeders ingested only 0.6 fibres per fish

Temperature also made a difference. At warmer temperatures (19°C):

  • Sardines expelled plastic fibres faster, likely due to faster digestion.

  • But they also ingested more plastic, probably because their metabolism increased and they needed more food.

Another discovery: Plastic fibres stayed in the sardines’ digestive system longer than real food. Half the food was gone in about 12–14 hours, but it took 23–25 hours to get rid of just half the plastic fibres.

The Health Impact on Sardines

Over the course of the experiment, filter-feeding sardines didn’t just eat more plastic—they also got weaker.

  • They lost more weight and had lower body condition scores compared to those eating larger particles.

  • Their stomachs were less full, which suggests they ate less food overall and didn’t get enough energy.

Interestingly, the plastic alone wasn’t what made them unhealthy. Instead, it was the combination of filter-feeding and warmer water that seemed to hurt them most. Warmer oceans can lead to smaller plankton, which makes filter-feeding more common—and that leads to more plastic being ingested.

Why This Matters for Climate and Human Health

The health of sardines isn’t just a fish problem—it’s an ocean problem and a human problem.

Here’s why this matters:

  • Warming oceans = smaller plankton

  • Smaller plankton = more filter-feeding by fish

  • More filter-feeding = more plastic consumed

If sardine populations continue to shrink:

  • Predators like tuna, dolphins, and seabirds could lose a key food source.

  • People who depend on sardines for protein or income may struggle.

  • Ocean ecosystems could become unbalanced.

These changes don’t happen in isolation. Climate change and plastic pollution often work together, creating stress that marine life—and people—may not be able to overcome.

What Can We Do?

The good news is that small changes on land can protect life in the sea. Here are a few steps anyone can take:

  • Choose clothes made from natural fibers (like cotton or wool). Washing synthetic clothes sheds plastic fibres into the water.

  • Reduce plastic packaging by using reusable bags, bottles, and containers.

  • Support ocean cleanup efforts and organizations that study microplastics.

  • Advocate for climate action, including clean energy and reduced carbon emissions, to help slow ocean warming.

  • Hold your local, state, and national elected officials accountable for taking climate action and protecting our water, air, and health.

A Call to Protect What Connects Us All

Sardines may not get much attention, but they’re part of a delicate chain that connects us all. When small creatures suffer, the effects can ripple through the food web—and onto our plates.

The choices we make on land ripple into the sea—and into our future.

By staying informed, reducing plastic use, and supporting climate action, we can help protect the ocean, our food systems, and the health of generations to come.

Source: Rodriguez-Romeu, O., Constenla, M., Soler-Membrives, A., Dutto, G., Saraux, C., & Schull, Q. (2024). Sardines in hot water: Unravelling plastic fibre ingestion and feeding behaviour effects. Environmental Pollution, 363, 125035. https://linkinghub.elsevier.com/retrieve/pii/S0269749124017500

Planetary Solvency: Why Our Future Depends on Protecting Nature

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Cover of 'Planetary solvency – finding our balance with nature: Global risk management for human prosperity' study.
Cover of “Planetary solvency – finding our balance with nature: Global risk management for human prosperity” study.

The Big Picture

Imagine waking up to find grocery store shelves half-empty, the price of fresh produce soaring, and unpredictable storms disrupting everyday life. This isn’t science fiction—it’s a growing reality as our planet’s climate shifts in dangerous ways.

Scientists warn that unless we change course, we risk reaching Planetary Insolvency—a state where nature can no longer support human needs. But here’s the good news: we still have time to act. Understanding the risks and making smarter choices today can help us create a future where people and nature thrive together.

What Is Planetary Solvency?

Think about a business. If it spends more money than it earns, it eventually goes bankrupt. Our planet works in a similar way—if we take more from nature than it can regenerate, we risk collapsing the very systems that support life.

Planetary Solvency is the idea that we must manage Earth’s resources wisely to keep society stable. This means keeping our air and water clean, protecting forests and oceans, and ensuring that nature continues to provide the essentials we rely on—like food, water, and a livable climate.

For decades, economies have focused on short-term profit without considering the environmental “debt” we’re racking up. Now, we’re starting to see the consequences—but it’s not too late to course-correct.

The Warning Signs: Key Statistics You Need to Know

Climate scientists and risk analysts have uncovered troubling trends that show just how urgent this issue is:

  • The past 12 months were the hottest on record, with global temperatures averaging 1.5°C above pre-industrial levels (Trust et al., 2025).

  • A key ocean current system (AMOC) has a 45% chance of collapsing by 2040. This would cause extreme weather shifts, including stronger hurricanes, longer droughts, and disrupted food production.

  • If global warming reaches 2.5°C, over 50% of land suitable for growing wheat and maize could be lost, making food shortages more common.

  • Economic risk models ignore 87% of industries, assuming they won’t be affected by climate change. This is a dangerous miscalculation—nearly all businesses depend on stable natural systems.

  • Some projections estimate that climate-driven disasters could reduce global GDP by up to 63% by 2100, leading to widespread economic instability.

The takeaway? Climate change isn’t just about rising temperatures—it affects food security, jobs, public health, and global stability.

Why Current Climate Plans Are Not Enough

Many governments have pledged to cut carbon emissions and protect ecosystems, but current efforts fall short. Here’s why:

  • The Paris Agreement didn’t account for tipping points: Climate disasters don’t happen in isolation. When one event (like Arctic ice melting) triggers another (such as changing ocean currents), the effects spiral out of control. Many climate policies fail to consider this domino effect.

  • Short-term economic focus: Many governments prioritize economic growth over environmental stability, even though our economy depends on nature—from agriculture to clean water to disaster resilience.

  • Underestimated risks: Climate models often leave out the worst-case scenarios because they are hard to predict. However, ignoring unlikely but catastrophic events is a major risk management failure.

In short, we need stronger and more realistic climate policies that recognize the full scale of the threat.

What Needs to Change: The RESILIENCE Plan

To prevent Planetary Insolvency, experts recommend a RESILIENCE-based approach, which includes:

  • Better Risk Assessments: Governments and businesses need realistic climate risk models—like financial audits, but for Earth’s health.

  • Stronger Policies: Enforceable limits on pollution, deforestation, and overfishing.

  • Faster Emissions Reductions: The longer we wait, the harder it becomes to prevent extreme warming.

  • Restoring Nature: Protecting and rebuilding ecosystems like forests and wetlands, which absorb carbon and prevent natural disasters.

  • Educating Leaders: Many policymakers lack a deep understanding of climate risk. We need climate-literate decision-makers who can balance economic growth with sustainability.

The path forward isn’t just about stopping damage—it’s about creating a world where nature and people thrive together.

What Can YOU Do?

While governments and businesses play a major role, individuals can make a difference too. Here are some ways to take action:

  • Stay Informed: Read about climate solutions, not just problems. Understanding what works can help shape smarter decisions.

  • Push for Policy Change: Vote for leaders and support policies that prioritize sustainability. Your voice matters.

  • Make Smarter Choices: Support businesses committed to sustainable practices. Reduce waste and be mindful of energy consumption.

  • Spread Awareness: Talk about these issues with friends and family. Many people want to help but don’t know where to start.

These small steps, when multiplied across millions of people, can drive real change.

Summing Up

The future isn’t set in stone. What we do today will determine whether our planet remains livable or spirals into crisis. By managing Earth’s resources as carefully as we manage money, we can protect future generations and ensure a stable, thriving world.The good news? We still have time to act—but the clock is ticking. Will we make the right choice?

Source: Trust, S., Saye, L., Bettis, O., Bedenham, G., Hampshire, O., Lenton, T. M., & Abrams, J. (2025, January). Planetary solvency – finding our balance with nature: Global risk management for human prosperity. Institute and Faculty of Actuaries & Exeter University.

National Parks at Risk: How Privatization Could Speed Up Climate Change

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Yosemite Valley, among the trees.
Yosemite Valley, among the trees, in June 2023. Credit: Diana Bald

America’s national parks are powerful and beautiful. They are scenic vacation spots and part of our shared heritage. They are home to countless wildlife species and natural protectors against climate change. Recently, concerns have grown about privatization—the idea of private companies taking over or managing aspects of our national parks. Why does this matter? Privatization could change how these lands are cared for, possibly speeding up climate change and limiting public access.

Below we’ll share what privatization is, why it’s happening, and how it might put our parks—and our planet—at risk. You’ll learn about potential harm to wildlife and ecosystems and see how private profit-seeking might increase carbon pollution. Finally, we’ll look at the different sides of the debate and share ways you can help protect these treasures for future generations.

What Is National Park Privatization?

Privatization of national parks means involving private companies in running parts of a park—or, in more extreme cases, selling park land. While the second option is very rare and highly controversial, there are other, more common ways private interests can step in.

  • Concessions: This is when private businesses manage hotels, restaurants, campgrounds, or gift shops inside a national park. A company might build and operate a lodge while paying fees to the government.

  • Public-Private Partnerships: The government owns the park but hires or partners with a private operator to handle daily services, like cleaning facilities or running visitor centers.

  • Outright Sale: In uncommon situations, park land could be sold to a private entity, meaning it is no longer publicly owned.

Why It’s Happening

Many parks have significant funding gaps. According to the National Park Service (NPS), national parks in the United States face an estimated $11.9 billion maintenance backlog, meaning there’s a lot of work that needs to be done—like fixing roads, upgrading water systems, and repairing trails—but not enough money to do it all. Some people believe private companies can fill this gap by bringing in their own funds and running things more efficiently.

Why Do People Worry About Privatization?

Privatization sometimes gives private businesses room to push for more development—like building bigger hotels or even introducing commercial activities in delicate areas. This can mean fewer trees to absorb carbon dioxide, more greenhouse gas emissions from construction, and more energy use to support amenities like large resorts (Source: National Parks Conservation Association (NPCA)).

Loss of Public Control

Our national parks belong to all of us. When for-profit companies take a bigger role, everyday citizens can lose their say in how these lands are used. Government agencies like the National Park Service aim to protect wildlife, natural beauty, and our shared heritage. Private companies have a duty to earn profits. These two goals don’t always line up.

Risk of High Prices and Limited Access

Private businesses often raise fees to cover costs and make a profit. That might include higher prices for overnight stays, guided tours, or even basic park entry. Imagine a scenario where only those who can pay premium rates get to enjoy our national treasures. That kind of setup could exclude families on a budget or students looking to learn about nature firsthand.

How Could Privatization Speed Up Climate Change?

Privately built hotels, roads, and resorts can encroach on forests or wetlands that store carbon. Removing trees or filling in wetlands releases carbon that was previously locked away in plants and soil, adding to the greenhouse gases warming our planet.

When privatization weakens environmental protections, there’s a chance that companies will seek permission to mine, drill, or log on public lands near or even within parks. Extracting natural resources not only increases carbon emissions but also disrupts critical habitats for animals and plants.

A private operator looking for higher profits might want to draw large crowds. More visitors can be wonderful for education and appreciation, but it can also mean more cars, heavier traffic, and longer lines, all leading to additional exhaust fumes and higher greenhouse gas emissions.

Harm to Wildlife and Ecosystems

Big developments like roads, fences, or commercial sites can cut wildlife habitats into smaller pieces. When animals can’t move around freely to find food or migrate, their populations may decline. This fragmentation makes ecosystems more fragile and less able to bounce back from natural disasters linked to climate change.

Reduced Biodiversity

National parks often safeguard a vast range of plant and animal species. Overbuilding, pollution, and noise can push away or endanger species—leading to a drop in biodiversity. Healthy ecosystems rely on a balance of predators, prey, and plants. When that balance is lost, the entire system can unravel.

Less Resilient Ecosystems

Forests, wetlands, and grasslands inside parks help lessen the worst impacts of climate change by storing carbon, stabilizing soils, and buffering against floods. If these areas become fragmented or polluted, they can’t protect us as effectively from the rising threats of wildfires, severe storms, or droughts (Source: United Nations Environment Programme).

Different Sides of the Argument

We’re stunned by the concept of loosing national parks that belong to all of us to private ownership of a few. Privatization supporters argue that private companies could bring much-needed funding, potentially fix aging facilities, and even offer new innovations—like using clean energy in park buildings. They also point out that private partnerships might generate jobs for local communities. Critics worry that a focus on profit could weaken conservation efforts, possibly leading to higher entrance fees that shut out families or lower-income visitors. They also warn that private operators may not face the same level of public oversight, which could make environmental regulations harder to enforce.

Arguments For Privatization

  • May bring more money to fix trails, roads, and park facilities.
  • Could create jobs in local communities, especially around tourism.
  • Potential for private innovation, such as using solar power in new building projects if the contract requires it.

Arguments Against Privatization

  • Profit motives overlook long-term conservation and climate goals.
  • Increased fees could limit public access and make visiting too expensive for many people.
  • Less accountability and oversight mean environmental standards may not be enforced strictly.

Actions Concerned Citizens Can Take

You don’t need a science degree or a powerful position to help protect our parks. Here are some ways you can make a difference:

  • Stay Informed
  • Speak Up
    • Contact your elected officials—call, email, or meet them at a town hall—and share your concerns about privatization proposals.
    • Write letters to local newspapers or post on social media to raise awareness.
  • Support Public Funding
    • Advocate for strong public budgets for parks. For instance, the Great American Outdoors Act helps fund maintenance and conservation projects without relying solely on private money.
    • Encourage your community to vote in favor of bond measures or other funding initiatives that keep parks public and well-maintained.
  • Volunteer and Donate
    • Donate to nonprofits dedicated to conservation and biodiversity.
    • Look for volunteer programs in local or national parks, where you can help maintain trails or educate visitors about conservation.

Final Thoughts

National parks belong to everyone. While privatization might seem like a quick fix to budget problems, it can have serious effects on our climate and on the health of these special places. Private operators could prioritize profits over the long-term well-being of wildlife and ecosystems, leading to more carbon emissions and less public involvement.

By staying informed, speaking up, and supporting strong public funding, you can help protect national parks for generations to come. Your voice matters in deciding how these natural wonders should be cared for. With a little effort, we can make sure our parks remain open, wild, and resilient in a changing climate—leaving a healthy legacy for those who come after us.

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