How Cutting Down Tropical Forests is Costing Lives Through Deadly Heat

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Animated map showing heat-related mortality rates linked to deforestation across Tropical Central and South America, with darker colors representing higher deaths per 100,000 people.
The maps show regions of Tropical Central and South America (a), Tropical Africa (b), and Southeast Asia (c). Colours show number of deaths per year per 100,000 people located in areas of forest loss (central estimate), aggregated by second-level administration divisions. Boundaries for second-level administration divisions are from GADM (https://gadm.org/index.html).

When we hear about deforestation, many of us think first about disappearing wildlife, endangered species, or the loss of carbon storage that slows climate change. All of that is true, but there’s another hidden danger. Cutting down tropical forests hurts our planet’s biodiversity and directly affects human health. New research shows that losing forests makes people hotter, sicker, and in many cases, more likely to die from extreme heat.

What the Study Found

A recent study published in Nature Climate Change looked at forest loss across the tropics between 2001 and 2020. The researchers found that when forests are cleared, the land surface warms up quickly. On average, deforested areas became almost 0.5 °C hotter than places that kept their trees.

That may not sound like much, but for people living in already hot, humid places, even small increases can push temperatures past safe limits. The study estimated that about 345 million people have been exposed to this extra warming caused by deforestation. That’s nearly the size of the entire U.S. population.

The Human Toll

The warming from deforestation is deadly. According to the study, deforestation is linked to about 28,000 extra heat-related deaths each year (Reddington et al., 2025). These deaths happen because the body can only handle so much heat before heart, lung, or kidney problems set in.

Some of the hardest-hit regions include:

  • Indonesia, Vietnam, and Malaysia, where heat deaths per 100,000 people are among the highest in the world.

  • Nigeria and the Democratic Republic of Congo, which also face significant impacts.

  • Southeast Asia overall, which accounts for more than half of all the deaths linked to deforestation-related heat.

In these countries, outdoor workers, such as farmers and construction workers, are especially vulnerable.

Why the Tropics Are Vulnerable

The tropics, regions close to the equator, are home to over 3.5 billion people. Many of these communities depend on outdoor work for their livelihoods. When forests are cut, not only does the land heat up, but shade disappears too. That makes outdoor work far more dangerous.

Health care access also plays a big role. In many tropical nations, hospitals and clinics are already under pressure, and people may not have reliable access to air conditioning, cooling centers, or emergency care. This limited ability to adapt means heat has a bigger impact on vulnerable groups, such as children, older adults, and outdoor workers.

Other Hidden Dangers

Heat isn’t the only risk linked to cutting forests. Deforestation also leads to:

  • Air pollution from fires: When forests are burned, smoke can spread across entire regions. In past years, haze from Indonesian forest fires exposed tens of millions of people to unsafe air, leading to thousands of premature deaths.

  • Spread of diseases: Clearing forests can increase the spread of diseases like malaria. In some places, standing water left after logging creates ideal breeding grounds for mosquitoes.

Together, these risks make deforestation not only an environmental problem but also a serious public health issue.

What Can Be Done

The good news is that protecting forests can prevent many of these heat-related deaths. Keeping trees standing provides shade, keeps local areas cooler, and reduces harmful smoke. On a larger scale, forests act as a buffer against climate change by storing carbon and releasing moisture into the air.

Steps that can help include:

  • Stronger protections for tropical forests through laws and enforcement.

  • Community-led conservation that involves local and Indigenous groups who know the land best.

  • Investment in health systems and cooling strategies to protect people who already live in areas affected by deforestation.

  • Global cooperation to reduce demand for products linked to deforestation, such as unsustainable palm oil, soy, and beef.

These actions can save thousands of lives each year.

Summing Up

The study’s message is clear: tropical forests aren’t just “carbon sinks” or wildlife havens. They are lifelines for millions of people. Losing them raises local temperatures, increases the risk of deadly heat, and harms human health in ways many of us never considered.

By protecting tropical forests, we preserve ecosystems while protecting people. Safeguarding these forests is a direct investment in healthier, safer communities around the world.

Source: Reddington, C. L., Smith, C., Butt, E. W., Baker, J. C. A., Oliveira, B. F. A., Yamba, E. I., & Spracklen, D. V. (2025). Tropical deforestation is associated with considerable heat-related mortality. Nature Climate Change. Advance online publication. https://doi.org/10.1038/s41558-025-02411-0

Will Climate Change Change Our Rainbows?

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A vivid rainbow arcs over the ocean with rocky cliffs in the foreground, under a cloudy sky.
A double rainbow stretches across the sky above a rocky coastline, showing the beauty and fragility of nature.

Rainbows are a universal symbol of hope, beauty, and wonder. They stop us in our tracks after a rainstorm and remind us of nature’s magic. But here’s a question we might not have asked before: What if climate change changes how often we see them?

For the first time, scientists have studied how global warming could reshape the distribution of rainbows around the world. The study, published in Global Environmental Change, is the first global effort to map rainbow distribution and explore how climate change may alter it (Carlson et al., 2022).

Purpose of the Study

Most climate change research looks at tangible impacts, such as rising seas, stronger storms, heatwaves, droughts, and wildfires. These are serious and urgent threats. But climate change is also transforming experiences in nature that are less obvious but still deeply meaningful to people.

This study focused on what scientists call cultural ecosystem services, the non-material benefits nature provides. These include inspiration, identity, and a sense of wonder. Rainbows fall into this category. The researchers wanted to answer a simple but profound question: How will climate change affect our chances of seeing a rainbow?

How the Study Was Conducted

To find out, the team gathered a unique dataset. They analyzed 7,094 geotagged rainbow photographs uploaded to Flickr between 2004 and 2013. These photos provided evidence of when and where rainbows appeared.

Using this information, the researchers built a model that predicted rainbow occurrence based on three main factors:

  • Sun angle (the position of the sun in the sky).

  • Cloud cover (whether clouds block sunlight).

  • Liquid precipitation (rain, not snow).

They then tested this model against climate projections for the year 2100 using three scenarios: low, moderate, and high emissions. This allowed them to estimate how rainbow sightings might change in the future.

Key Statistics and Findings

The results revealed some fascinating numbers:

  • 117 ± 71 rainbow-days per year: On average, each land location today experiences this many days with at least one rainbow.

  • 4.0–4.9% increase by 2100: Overall, climate change is projected to slightly increase rainbow-days worldwide.

  • 21–34% of land areas will lose rainbow-days, while 66–79% of land areas will gain them.

  • Regional losses are projected in the Mediterranean, Brazil, southern Africa, and southern Australia.

  • Regional gains are expected in Alaska, northern Europe (e.g., Norway), the Tibetan Plateau, Korea, Japan, and eastern Borneo.

  • The model had 86% accuracy overall, with 75% accuracy in predicting rainbows (Carlson et al., 2022).

In other words, while the planet as a whole may see more rainbows, the distribution will shift. Some regions may lose rainbow opportunities, while others gain them.

Why These Results Matter

On the surface, a change in rainbow frequency may seem trivial compared to rising seas or food shortages. But the implications go deeper.

Rainbows carry cultural meaning. Across societies, they symbolize hope, spirituality, peace, and connection. A decline in rainbow sightings in certain regions could weaken traditions and shared experiences tied to them.

Human wellbeing is linked to nature. Research shows that spending time in nature improves mental health and happiness. Rainbows, as brief and beautiful events, strengthen those connections.

Losses will be uneven. Some of the areas projected to lose rainbow-days, such as the Mediterranean and Brazil, are home to large populations. Meanwhile, many of the regions projected to gain rainbow-days, such as northern latitudes and high mountain areas, have fewer people. This means fewer communities will benefit from the increases.

By studying rainbows, the researchers remind us that climate change affects more than just physical dangers. It also shapes the beauty and meaning we find in our surroundings.

The Bottom Line

Climate change isn’t only about floods, storms, and heat. It also changes the beauty we see in the sky. Rainbows may become more common in some places, but less so in others. And while the net global number of rainbow-days may rise, the loss in culturally rich and populated areas could carry emotional and social costs.

The message is clear: protecting the environment means more than ensuring survival. It also means safeguarding the inspirational wonders of nature that make life richer, from the birds we hear at dawn to the rainbows that appear after a storm.

If we act to reduce emissions and protect our climate, we’re not only preventing disasters, we are protecting the everyday magic that reminds us why the Earth is worth fighting for.

Source: Carlson, K. M., Mora, C., Xu, J., Setter, R. O., Harangody, M., Franklin, E. C., Kantar, M. B., Lucas, M., Menzo, Z. M., Spirandelli, D., Schanzenbach, D., Warr, C. C., Wong, A. E., & Businger, S. (2022). Global rainbow distribution under current and future climates. Global Environmental Change, 77, 102604. https://linkinghub.elsevier.com/retrieve/pii/S095937802200142X

Tropical Bird Populations Plummet

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A Warning Sign for Our Planet

Two colorful tropical parrots perched side by side, one red-and-green and the other blue-and-yellow, against a backdrop of green foliage.
Tropical parrots, key seed dispersers and pollinators, highlight the biodiversity at risk as climate change accelerates bird population declines.

Why Tropical Birds Matter

When we think of the tropics, we often picture the sounds of colorful birds echoing through lush forests. From toucans and parrots in South America to hornbills in Asia and turacos in Africa, tropical birds are more than just symbols of beauty, they’re vital to keeping these ecosystems alive.

But new research published this week in Nature Climate Change delivers sobering news: tropical bird populations are collapsing. In many regions, numbers have dropped by more than half in just 30 years. These declines are warning signals that the ecosystems we all depend on are under threat.

The Study at a Glance

  • Published: August 2025
  • Source: Nature Climate Change
  • Finding: Many tropical bird species have lost more than 50% of their populations over three decades.
  • Causes: Deforestation, climate shifts, habitat fragmentation, and food scarcity.

Researchers analyzed decades of data from South America, Africa, and Southeast Asia. The breadth of the study makes it one of the strongest indicators yet of how climate change and human activity are reshaping entire ecosystems.

Why This Matters Beyond Birds

It may be tempting to think of this as a bird problem, but in reality, it’s a human problem. Birds play critical roles in the health of tropical forests. Many tropical plants rely on birds for pollination, making them essential partners in sustaining rainforest ecosystems. Birds also serve as seed dispersers, carrying seeds across vast distances and helping forests regenerate after storms, fires, or human disturbance. In addition, they act as natural pest control by consuming insects, which reduces crop damage and lowers the risk of diseases spreading.

If these birds vanish, the balance tips. Forests struggle to regenerate, pests multiply, and ecosystems weaken, leading to ripple effects that reach people everywhere. Think of birds as the “canaries in the coal mine” of the tropics. Their decline signals deeper problems unfolding quietly but rapidly.

What’s Driving the Decline?

The study highlights several overlapping causes:

  • Deforestation: Vast areas of tropical forest are cleared each year for farming, logging, and development. Birds lose nesting sites and food sources.

  • Climate Change: Rising temperatures disrupt breeding cycles, while shifting rainfall patterns reduce insect and fruit availability.

  • Habitat Fragmentation: When forests are broken into small, isolated patches, bird populations struggle to survive.

  • Direct Human Pressure: Hunting and the pet trade further threaten vulnerable species.

Together, these pressures create a perfect storm, pushing many species toward decline faster than conservation measures can keep up.

Lessons for the Rest of the World

What happens in the tropics doesn’t stay in the tropics. Healthy forests regulate Earth’s climate by absorbing massive amounts of carbon dioxide. Without birds to keep these forests resilient, the planet’s ability to fight climate change weakens.

In other words: when tropical birds decline, so does one of our best natural defenses against global warming.

Hope in Action

While the data is troubling, the study also points toward hope. Around the world, conservation efforts have proven effective when communities, governments, and organizations work together.

  • Protected Areas Work: Expanding reserves and enforcing protections stabilize bird populations.

  • Reforestation Efforts: Planting diverse native trees provides food and shelter.

  • Community-Led Conservation: When local people are empowered to steward forests, biodiversity thrives.

  • Climate Action: Reducing greenhouse gas emissions protects fragile ecosystems long-term.

Small victories are already happening. In Costa Rica, large-scale reforestation has allowed once-declining bird populations to rebound. Similar projects in Indonesia and parts of Africa show that recovery is possible with the right support.

What You Can Do

The tropical bird crisis may feel far away, but every choice we make has global consequences. Here are practical ways to help:

  • Support conservation groups working in tropical regions.

  • Choose sustainably sourced products like certified coffee or wood.

  • Advocate for strong climate policies in your community and beyond.
  • Reduce personal carbon footprints through energy choices and transportation.

Even small actions add up. Just as a single bird can carry seeds that grow into a new forest, one person’s choices can contribute to a healthier planet.

Birds keep forests alive, and forests keep our planet stable. If they falter, so do we. By protecting habitats, addressing climate change, and supporting conservation, we can ensure that the forests remain full of life, and that their songs continue for generations to come.

Source: Goldwert, D., Patel, Y., Nielsen, K. S., Goldberg, M. H., & Vlasceanu, M. (2025). Climate action literacy interventions increase commitments to more effective mitigation behaviors. PNAS Nexus, 4(6), pgaf191.