How Our Skies Are Changing in a Warming World

We spend so much time looking at the ground, at our phones, or just straight ahead. But when was the last time you truly looked up? At the vast expanse of the sky, from the brilliant daytime sun to the glittering tapestry of night? It’s a constant in our lives, a backdrop to every outdoor adventure, every memory. Yet, even the sky, seemingly boundless and untouchable, is changing in ways both subtle and dramatic, influenced by the very climate shifts happening on Earth.

After years of immersing myself in climate science – the books, the documentaries, the endless news cycles – I’ve realized that the impact of human-caused climate change extends far beyond just temperatures and sea levels. It’s affecting the very air we breathe, the light we see, and our connection to the cosmos. This isn’t about fear; it’s about understanding and appreciating these changes, and recognizing our role in shaping the sky our children will inherit.

UV Exposure: The Hidden Intensity

We’re all aware of the dangers of UV radiation, especially UV-B, the more harmful type that causes sunburn and skin damage. For a long time, the primary concern was ozone depletion, which allowed more UV-B to reach the surface. Thankfully, international efforts like the Montreal Protocol have largely addressed this, and the ozone layer is slowly recovering.

However, the story of UV and climate change is more complex. While ozone depletion is distinct from climate change itself, climate change can indirectly influence UV exposure in a few ways:

• Behavioral Changes: As temperatures rise, we tend to spend more time outdoors, and wear lighter clothing, which naturally increases our exposure.
• Reduced Cloud Cover (Regionally): While overall cloud cover trends are complex and vary, some regions are experiencing prolonged periods of clear skies due to climate-related patterns (like the heatwaves seen in Europe). Fewer clouds mean less UV scattering and higher direct exposure.
• Aerosol Reduction: Efforts to reduce air pollution (which is a good thing for our lungs!) can sometimes lead to an increase in ground-level UV. Pollutants and aerosols actually scatter and absorb some UV radiation. As air quality improves in some areas, we might see a slight increase in direct UV.

The key takeaway here is vigilance. Regardless of the complex atmospheric dynamics, higher temperatures often mean we’re spending more time in the sun, making sun protection – hats, UPF clothing, sunscreen – more critical than ever.

Sunsets: The Art of Atmospheric Optics

Who doesn’t love a spectacular sunset? Those fiery reds, deep oranges, and vibrant purples are the result of sunlight scattering through the Earth’s atmosphere, particularly dust, aerosols, and water vapor. So, how might climate change paint our future sunsets?

• Wildfire Smoke: This is perhaps the most direct and dramatic impact. As climate change fuels more frequent and intense wildfires globally, smoke plumes containing vast amounts of aerosols can travel thousands of miles. These tiny particles scatter sunlight in ways that greatly enhance the red and orange hues, creating incredibly vivid, almost apocalyptic, sunsets. While beautiful, they are a stark reminder of environmental distress.
• Dust and Pollution: Desertification and changing wind patterns driven by climate change could increase airborne dust. Additionally, while some areas are cleaning up air pollution, others, particularly rapidly industrializing regions, might see an increase in particulate matter. Both dust and pollution can contribute to more vibrant, though not necessarily healthier, sunsets by scattering light more effectively.
• Cloud Changes: Climate models are still working to fully understand how cloud cover will change globally. More clouds can block sunsets entirely, while certain types of clouds, particularly high-altitude cirrus clouds, can catch the last rays of light, adding to the spectacle. The balance of these factors will influence future sunset views.

So, ironically, some of the most stunning sunsets we witness might become a visual byproduct of our changing climate, a beautiful, yet bittersweet, reminder of the atmospheric shifts happening around us.

Stargazing: Losing Our View of the Cosmos?

This is where the climate change story for our skies gets a little more somber, particularly for those of us who cherish the wonders of the night sky.

• Increased Cloud Cover and Humidity: While the overall global trend for clouds is still being refined by models, many climate projections suggest an increase in atmospheric moisture and cloud cover in certain regions. More clouds directly translate to fewer clear nights suitable for stargazing. Higher humidity also scatters light more effectively, blurring our view.
• Atmospheric Turbulence: A warming atmosphere can lead to increased atmospheric turbulence. For professional observatories, this “seeing” condition directly impacts the sharpness of images. For amateur stargazers, it might translate to a less crisp view of planets or nebulae.
• Wildfire Haze: Just as with sunsets, wildfire smoke can linger for weeks, creating a persistent haze that severely obstructs views of the stars and deep-sky objects. The skies that once offered pristine views of the Milky Way can become a uniform, murky gray.
• Light Pollution (Indirect Climate Link): This is perhaps the most immediate threat to stargazing. While not a direct climate change effect, there’s an indirect link: as heatwaves become more intense, human activity might shift more towards cooler nighttime hours, potentially leading to increased outdoor lighting and, consequently, more light pollution. This skyglow, which is already doubling in brightness every eight years globally due to inefficient or excessive lighting, is rapidly erasing the stars from view for much of the world’s population. It’s a wasteful use of energy, contributing to the very greenhouse gas emissions that drive climate change.

Where will it get better/worse? Remote, high-altitude desert locations (often where professional observatories are located) might still offer the best conditions, assuming they aren’t impacted by increased regional cloudiness or wildfire smoke. However, for most populated areas, stargazing will likely continue to get worse due to the combined effects of light pollution, and climate-induced haze and cloud cover. Even traditionally dark sky areas could face increased cloudiness or smoke.

We spend so much time looking at the ground, at our phones, or just straight ahead. But when was the last time you truly looked up? At the vast expanse of the sky, from the brilliant daytime sun to the glittering tapestry of night? It’s a constant in our lives, a backdrop to every outdoor…