The atmosphere of the Archean eon—one-third of Earth's history—is important for
understanding the evolution of our planet and Earth-like exoplanets. New geological proxies …

The present paper addresses driving mechanisms of global monsoon (GM) variability and
outstanding issues in GM science. This is the second synthesis of the PAGES GM Working …

In 2017, western Canadian wildfires injected smoke into the stratosphere that was
detectable by satellites for more than 8 months. The smoke plume rose from 12 to 23 …

Recognizing whether a planet can support life is a primary goal of future exoplanet spectral
characterization missions, but past research on habitability assessment has largely ignored …

The search for life in the Universe is a fundamental problem of astrobiology and modern
science. The current progress in the detection of terrestrial-type exoplanets has opened a …

The origin of life on Earth seems to demand a highly reduced early atmosphere, rich in CH
4, H 2, and NH 3, but geological evidence suggests that Earth's mantle has always been …

A long-term goal of exoplanet studies is the identification and detection of biosignature
gases. Beyond the most discussed biosignature gas O2, only a handful of gases have been …

Observations of exoplanet atmospheres have shown that aerosols, like in the solar system,
are common across a variety of temperatures and planet types. The formation and …

Chemical disequilibrium in planetary atmospheres has been proposed as a generalized
method for detecting life on exoplanets through remote spectroscopy. Among solar system …

On the basis of geological evidence, it is often stated that the early martian climate was
warm enough for liquid water to flow on the surface thanks to the greenhouse effect of a thick …