We know more about microclimates than we think. We’ve all felt that warmer, denser air upon entering a city. Or the sudden coolness when stepping into a shady forest, as the temperature drops, the noise softens, and the humidity wraps around us. Those who live in desert regions are familiar with the subtle threshold that marks the entrance to an oasis: the exact moment when the scorching air softens, the wind shifts, and life reappears.

Technically, a microclimate is a local environment with thermal, hydrological, and atmospheric characteristics that differ from the surrounding area. It can be as small as an urban garden or as vast as an oasis in the desert.

It is shaped by factors such as land orientation, altitude, vegetation, proximity to water, or even building materials. These differences—a few degrees, a bit more moisture, a few extra seconds of shade—can mark the boundary between life and the impossibility of life for many plant and animal species.

Today, from a human perspective, we can classify microclimates into two broad groups:

• Anthropogenic, generated by human activity. These are often harmful to the biosphere. The clearest example is the “heat islands” that form in large cities and industrial centres.
• Natural, which have existed for millennia and are part of the planet’s ecological balance. They occur in oases, forests, shady valleys, oceanic atolls, lakes, alpine glaciers…

Scientists warn: natural microclimates are in decline, while urban and industrial ones continue to expand.

The urban microclimate is the most critical for the future of the global population, as over 70% of people will live in cities within a few decades. We have explored the phenomenon of urban heat islands in other articles: dense, paved, and highly built-up cities that trap heat like ovens. Large, high-density urban areas tend to form thermal bubbles that are much more intense than smaller cities or those with greater green coverage.

Recent studies confirm it: temperatures in central Paris or London are typically 2 to 3°C higher than in their rural outskirts. In Los Angeles—considered one of the most intense heat islands on the planet—the city centre can be more than 5°C hotter than less urbanised zones.

These urban microclimates are not uniform: within them, other microclimates exist—like thermal nesting dolls—where the shade of a tree or a breeze in a park can mean the difference between discomfort and relief.

More and more cities, like Barcelona, are identifying and signalling urban climate shelters: shaded pedestrian zones, schools and civic centres with green coverage, and marked gardens offering respite from heat waves.

Fighting the urban heat island involves maximising the recovery of natural soil: land, landscape, sanitation, and rain are all part of an urban ecosystem whose heart is water.

At the opposite end, oases—explored in more depth in another article—are perhaps the most iconic beneficial microclimate in popular culture. In the middle of desert regions dominated by heat and drought, they emerge as delicate natural and human systems: fertile soils, underground water sources, and vegetation that provides shade, moisture, and food. Climate change—together with aquifer overexploitation and urban expansion—is threatening their persistence. Some historic oases are already disappearing.

There are less visible microclimates that are nonetheless essential for planetary balance. Two stand out with growing importance in climate studies:

• Oceanic islands. Shaped by winds and currents, they host unique endemic biodiversity. Changes in oceanic patterns, sea level rise, and acidification are destabilising these insular microclimates, with irreversible consequences for their ecosystems.
• Cloud forests.Those in the Andes, East Africa, and Central America capture fog and regulate the water cycle. In tropical mountains, they trap moisture and moderate temperature like true climate sponges. They are vital for biodiversity and the water supply of large regions. Rising temperatures and the upward shift of cloud layers are putting them at risk.

Areas with distinct climates play a key role in maintaining the balance of the biosphere and driving the water cycle. Two of their effects are particularly relevant today:

• They host highly specialised species. The most well-known case is that of migratory species, which depend on very specific conditions in the stopover sites along their journeys. When those conditions disappear, species may not be able to adapt or relocate: competition, displacement, or local extinction can occur. This affects pollinators, soil insects, birds, and fungi that are crucial to ecological balance.
• They regulate the water cycle. The recharge of aquifers depends largely on the climatic conditions created in their surroundings. When an aquifer is destroyed, the microclimate it supported often deteriorates—and rarely recovers.

In its latest report (AR6), the IPCC warns that climate change not only alters major atmospheric systems but also erodes microclimates, stripping them of their specificity.

In urban environments, more intense and prolonged heatwaves are exceeding the capacity of parks and gardens to mitigate heat, while the spread of concrete erases local temperature variations that once offered relief to the most vulnerable populations.

At the same time, the IPCC alerts that biodiversity is losing its climate refuges. As mentioned earlier, ecosystem fragmentation and rising temperatures are levelling out once-unique conditions. Many species adapted to very specific niches—such as those relying on the damp shade of a cloud forest or the cool air of a canyon—are now at risk of extinction.

AR6 is clear: if we surpass the +1.5 °C threshold, many microclimates will stop functioning as buffers. And with them, we will lose not only biodiversity, but also natural solutions to cool, filter, and sustain life.

The global affects the local—and vice versa. Ecologists and climate scientists agree that restoring and protecting microclimates is a powerful local strategy in the face of climate change.

There are success stories—urban greening, reforestation near farmland, and regenerative agriculture—that show saving microclimates is both possible and beneficial for larger-scale systems.

Microclimates remind us that climate change is not only measured in global degrees, but also in local imbalances. Understanding, protecting, and regenerating them is not just an environmental issue: it is a tangible way to defend biodiversity, health, and the habitability of the planet.