The idea that life on Earth might eventually cease is not an alarmist prediction of immediate disaster, but rather a projection rooted in stellar and planetary evolution over very long time-scales. Recent research – including work drawing on the efforts of scientists associated with NASA and other institutions – offers updated estimates of when Earth’s biosphere may no longer support complex life, or possibly all life. This article reviews the key science behind these projections, explains the mechanisms involved, highlights major assumptions and uncertainties, and examines what this means for planetary habitability and the longevity of life on Earth.
The scientific basis: Sun-Earth evolution and biosphere limits
Life on Earth persists because our planet exists in a delicate balance of astrophysical, geological and biochemical processes. But over geological time-scales, those conditions will change.
Solar brightening and planetary warming
Over billions of years, our Sun will gradually increase in luminosity. As a main-sequence star its output slowly rises, exposing the Earth to progressively more heat. This increasing solar flux means Earth will receive more energy, pushing surface conditions toward higher temperatures, accelerating the water cycle and speeding up rock weathering. One result is accelerated consumption of CO₂ via the carbonate–silicate geochemical cycle, which gradually diminishes greenhouse buffering and ultimately impairs habitability. The concept of the habitable zone emphasises that a planet’s habitability is sensitive to the stellar output and how it evolves.
Atmospheric evolution, CO₂ and oxygen
Researchers have modelled how atmospheric composition and biosphere productivity will evolve over deep time. One important paper, “The future lifespan of Earth’s oxygenated atmosphere” by Ozaki & Reinhard (2021), uses a combined biogeochemistry-climate model to estimate that Earth’s atmosphere – with oxygen levels above ~1% of the present – has a mean future lifespan of about 1.08 ± 0.14 billion years. Their model shows that as solar luminosity increases, the carbonate–silicate cycle will draw down CO₂, which then limits photosynthesis, causing atmospheric oxygen to drop dramatically.
A more recent study, “Substantial Extension of the Lifetime of the Terrestrial Biosphere” by Graham, Halevy & Abbot (2024), re-examines the time remaining for terrestrial plants by considering updated parameterisations of weathering sensitivity to temperature and CO₂. Their results suggest that, under more optimistic assumptions, the survival time of terrestrial plants might extend from ~1 billion years up to roughly ~1.6-1.86 billion years before extreme temperatures halt photosynthesis.
Key projected milestones
Putting these elements together, one can sketch a rough timeline (with the caveat that these are approximate):
In about ~1 billion years Earth may face CO₂ levels too low for many land plants to photosynthesise, oxygen levels may plummet, and complex multicellular life would face strong survival challenges. In the ensuing 1-2 billion years surface temperatures may rise further, water may be lost from the surface more rapidly, and life may increasingly retreat to extreme niches (deep sea, subsurface). In perhaps ~2-3 billion years plate tectonics may slow or cease, the planetary magnetic dynamo may weaken, surface conditions may become extreme, and even microbial life may struggle. The Wikipedia “Timeline of the far future” lists roughly ~2.8 billion years as one estimate for when Earth may no longer support life in its current form.
Hence, while there is no precise “day” pinned down with high precision, current research suggests that the oxygen-rich biosphere we know may not persist beyond roughly 1 billion years, and that full biosphere viability may fade in perhaps 1-2 billion years (or longer under favourable assumptions).
What does this mean for “all life on Earth”?
It is important to distinguish what is meant by “life” and what is meant by “end”.
When scientists talk of a biosphere collapse or the “end of complex life”, they often mean multicellular plants and animals (especially land plants and animals) rather than extremophile microbes. Many of these models project the end of Earth’s modern oxygen-rich atmosphere or the end of surface habitability for many organisms, rather than the abrupt extinction of all life. For example, the Ozaki & Reinhard model emphasises that after de-oxygenation the Earth system will likely transition into a world dominated by anaerobic microorganisms.
Thus, while the research points to an endpoint for the familiar biosphere of plants and animals, it does not make a definitive prediction that every single organism will vanish on a precise date. Microbial life in extreme or subsurface environments may persist far longer (though perhaps not indefinitely).
Why this research matters
Why should we care about how long life on Earth can continue, particularly when the timescales are extremely long? There are several important reasons.
First, understanding planetary habitability over time is important: these studies improve our understanding of what makes a planet habitable not just now but billions of years into the future – which has implications for astrobiology (the search for life on other planets). The fact that Earth’s oxygen-rich state may be temporary implies that when we search for life on exoplanets we must consider that we might be observing a planet in a late stage of its habitability window. Second, these research findings offer perspective on Earth’s systems: they show that the biosphere we live in is not permanent but transient in geologic time. Acknowledging that helps frame our place in Earth’s long history and its future. Third, the work highlights the geological and biological interplay: habitability depends not just on biology, but also on astrophysics (sun’s evolution), geochemistry (weathering, tectonics) and atmosphere–ocean–biosphere feedbacks. Fourth, they foster long-term thinking: while human lifespans are short compared to these timescales, understanding that Earth’s habitability is finite may encourage broader thinking about the legacy of life, ecosystem resilience, and our planet’s future trajectory.
Assumptions and uncertainties
It is important to keep in mind that these projections carry many uncertainties. Among the key caveats are the following.
These models depend heavily on model assumptions: how fast the Sun brightens, how strongly weathering depends on temperature and CO₂, how plants respond to declines in CO₂ and increases in temperature, how plate tectonics and volcanic outgassing evolve, how oceans and atmospheres respond, etc. The resilience of life in extreme niches (deep subsurface, hydrothermal vents, etc.) is poorly constrained, making predictions of “life’s end” inherently uncertain. Some models assume no dramatic external catastrophe (asteroid impact, super-volcano, gamma-ray burst) which could accelerate or alter the timeline. The timeframe “about 1 billion years” is not a precise date – it is an order-of-magnitude estimate. Indeed, the Graham et al. study indicated that under alternative assumptions land plants might persist until ~1.6-1.9 billion years. Finally, because the phrase “life” is ambiguous in everyday use (does it mean multicellular animals? all organisms? only surface life?), caution is required in interpreting media headlines.
Implications for humanity and our era
From the human viewpoint, several reflections are worth noting. Although a billion years is an unimaginably long time compared to a human lifespan or civilisation scale, the processes that govern habitability (carbon cycles, atmospheric composition, ecosystem resilience) also operate on shorter timescales. Recognising that Earth’s habitability window is finite may influence how we think about our legacy and the environment we inherit. While humanity is not the driver of solar brightening or the deep geochemistry of the Earth system billions of years ahead, our actions do matter for the near-term habitability of ecosystems and for preserving life’s diversity for as long as reasonably possible. In addition, the research has relevance for astrobiology and civilisation’s future: if the window of complex life on Earth is finite, then questions arise about where in that window our civilisation currently sits, how long technological societies might last (assuming they persist toward the end of that window), and what it might mean for life and intelligence elsewhere. Finally, understanding that Earth’s biosphere will eventually change in irreversible ways can shift our perspective on what “normal” means. The Earth system we live in is a transitional state in a long planetary history – it is not the end, but it is also not the “forever” baseline.
Summary
Research modelling long-term planetary and biosphere evolution (notably the studies by Ozaki & Reinhard (2021) and Graham et al. (2024)) suggests that Earth’s modern oxygenated biosphere may not persist beyond roughly 1 billion years under current assumptions, though under more optimistic assumptions land plants may last up to ~1.6-1.9 billion years. Neither study claims a precise “end date” for all life, but both estimate when the conditions for large multicellular life become unsustainable and when the familiar oxygen-rich biosphere may collapse. After that, microbial and extreme-niche life may persist far longer, but the planet would be significantly different from today. These findings matter for our understanding of Earth, habitability, and the search for life on other worlds – and they offer a long-term perspective for how life on our planet might evolve.
Appendix – Recent Research Papers
- “Substantial Extension of the Lifetime of the Terrestrial Biosphere” by R. J. Graham, Itay Halevy & Dorian Abbot (2024) – This study models terrestrial plants, silicate weathering, climate and CO₂-dependency and finds that under weaker temperature-dependence of weathering the survival time of land plants may extend from ~1 billion years up to ~1.6-1.86 billion years. Relevance: sharpens the timescale for complex life survival on Earth and analogues.
- “The effect of a biosphere on the habitable timespan of Earth-like planets” by D. Höning et al. (2025) – This paper explores how a surface biosphere influences planetary habitable timespan via biological productivity feeding back on silicate weathering, showing that under some mantle/tectonic states, the habitable window may extend by ~1 Gyr. Relevance: emphasises biological feedback in models of planetary habitability and longevity.
- “Biotic feedback extends the life span of the biosphere” by T. M. Lenton & W. von Bloh (2025) – (Preliminary release) This conceptual work revisits how life itself can extend planetary habitability by stabilising climate via weathering feedbacks. Relevance: reinforces that life may not simply be passive but can extend habitability.
- “Land Fraction Diversity on Earth-like Planets and Implications for their Habitability” by D. Höning & Tilman Spohn (2022) – Although slightly older, this study shows that differences in land/ocean distribution can affect weathering rates, biosphere productivity and hence habitability lifetimes. Relevance: adds context to how planetary surface geography influences long-term biosphere viability.
- “Strong Evidence that Abiogenesis Is a Rapid Process on Earth-like Planets” (2025) – This paper argues that life’s origin on Earth-like planets may occur rapidly once conditions permit. Relevance: although not directly modelling the end of life, it influences how one models the window of habitability and “hard steps” in evolutionary timelines.
