Climate science asks us to accept a lot at once.

By Joseph Howlett

Earth’s climate system is famously chaotic, and slight changes to atmospheric conditions can produce wildly different outcomes. At the same time, we know for certain that adding more carbon dioxide to the atmosphere causes the planet to warm. This essay explores how climate scientists contend with these seemingly at-odds truths, a perspective that helps square uncertainty and the need for action.

By Mark Belan and Joseph Howlett

Even with human emissions, carbon dioxide makes up a tiny portion — just 0.042% (420 parts per million) — of all the gaseous molecules in the atmosphere. Those relatively few molecules are altering the energy balance of our entire planet. But how? Recent advances in understanding the quantum mechanics of greenhouse gases explain how some molecules trap heat.

By Zack Savitsky

Over the past 60 years, climate scientists have largely succeeded in building a computer model of the planet, capturing the most relevant processes of an impossibly complex system to see what the future holds. Now many of their predictions are being borne out and the impacts of climate change are becoming inescapable. At the same time, climate modeling faces threats from those who don’t like the answers it provides.

By Peter Brannen

By combining geoscience and global climate modeling, researchers are reconstructing 540 million years of Earth’s past climates, revealing a staggering variety of former worlds — from blistering hothouses to frigid icehouses and everything in between. The models underscore carbon dioxide’s principal role in our planet’s thermostat, and the rarity and vulnerability of our temperate moment.

By Katherine Bourzac

For billions of years before humans altered the atmosphere, microbes were the biosphere’s climate regulators. Today, they invisibly mediate climatic processes — from cloud formation to carbon storage to greenhouse gas production. This collection of dispatches from climate microbiology conveys the contributions that single-celled life forms make to our climate system and how we can work with them to address climate change.

By Gregory Barber

The most apocalyptic predictions of climate change — runaway ice melt and sea level rise, desertification of the Amazon rainforest and ocean currents going slack — rest on tipping points, which describe a system suddenly shifting from one stable state into another. While dramatic, the math of tipping points is wildly uncertain. Can mathematicians make it useful?

By Robin George Andrews

Venus is often considered Earth’s twin. The planets formed at the same time, from the same geologic building blocks, in pretty much the same part of the solar system. Yet Venus is a smoldering hellscape, with 96% carbon dioxide in its atmosphere — and some scientists believe it is a preview of Earth’s future. A team of researchers pushed a model of Earth to the brink of Venus to learn how long our planet might remain habitable.

By Gaia Vince

The story of life is the story of energy. Starting with the first life forms at hydrothermal vents, life has ratcheted up in complexity as it developed new ways to harness energy — up to humanity, whose hunger for it now extends across the planet. Through climate science, we have knowledge of our planetary impact, giving us the opportunity, and the responsibility, to secure the livability of our biosphere.