How Does Life Begin and Develop?
Objective
1
Sources of 0rganics on Earth
Objective
2
Origin of Life's Cellular Components
Objective
4
Genomic Clues to Evolution
Objective
5
Linking Planetary and Biological Evolution
Does Life Exist Elsewhere in the Universe?
Objective
7
The Extremes of Life
Objective
8
Past and Present Life on Mars
Objective
9
Life's Precursors and Habitats in the Outer Solar System
Objective
10
Natural Migration of Life
Objective
11
Origin of Habitable Planets
Objective
12
Effects of Climate and Geology on Habitability
Objective
13
Extrasolar Biomarkers
What is Life's Future on Earth
and Beyond?
Objective
14
Ecosystem Response to Rapid Environmental Change
Objective
15
Earth's Future Habitability
Objective
16
Bringing Life with Us beyond Earth
Objective
17
Planetary Protection
Question:
What is Life's Future on Earth and Beyond?
Earth's
Future Habitability
Objective 15: Model the future habitability of Earth by examining the interactions between the biosphere and the chemistry and radiation balance of the atmosphere.
Life on Earth has been so successful that the very environmental conditions needed to support present-day life forms are strongly coupled to -- and modified by -- ecological processes. The chemistry of Earth's atmosphere is strongly influenced by life. For example, the evolution of oxygenic photosynthesis ultimately led to an oxygen-rich atmosphere and to the development of the protective ozone layer to block lethal fluxes of ultraviolet radiation. The production and consumption of radiatively-active trace gases -- which influence global temperatures--are mediated by microbial and plant ecosystems. In the near-future, human-induced changes in levels of carbon dioxide and trace gases will alter the radiation balance of the atmosphere. In the more distant future, long-terms trends in biogeochemical cycling and solar luminosity will drive environmental changes that will compel the biosphere to adapt. Therefore, the environmental conditions of a habitable planet are influenced, not only by external and geological factors, but also by the biosphere, including humanity, and how it has evolved.
Implementation
Near- to mid-term:
- Define, through both remote
sensing analysis using the Earth Observing System and aircraft, as well
as new laboratory and field ecology experiments, aspects of the chemistry
of Earth's atmosphere that are strongly dependent on ecological processes
and biogenic trace gas fluxes.
- Develop new observations of
the oceans and terrestrial surface that can be incorporated into coupled
models of global atmospheric chemistry, and to the extent possible,
used to hindcast into the past for calibration and to predict into the
future.
- Develop models of Earth's historical biogeochemistry, and combine these with retrospective experimental studies to understand the geochemical relations of ecosystems and organism-level studies of physiological capacity.
Future extensions:
- Use computer modeling and remote sensing data analysis to develop new theories of the potential non-linear responses that can be expected in coupled biosphere-atmosphere systems. Support the coupling of Atmospheric General Circulation Models (AGCMs) with paleo-ecological observations and modern satellite perspectives of the Earth's changing biosphere.