NATURE|Vol 450|6 December 2007 EARTH MONITORING ESSAY Whole Earth comes into focus To understand how our planet uses energy, we must integrate genetic data from microbial studies with satellite views of our planet.

Stewart Brand

Two vastly different but complementary KAPUSTA J. projects could transform our understand- ing of Earth. The long-standing mystery of how microbes run the world is closer to being solved, thanks to metagenomics — the DNA sequencing of whole popula- tions of microbial life. And if a project to record fluctuations in the solar energy that reaches Earth gets back on track, we could begin to predict, and even manipulate, eco- logical changes on the planetary scale. In 1966, I promoted the idea of photo- graphing the ‘whole Earth’ from space, hoping that it would stimulate humanity’s interest in its mega-habitat. The concept of the whole-Earth photo expanded pro- foundly in 1998 when the then US vice- president, Al Gore, envisaged a video camera in space permanently broadcast- that in turn drive climate dynamics? uptake by microbes can be probed locally ing a high-resolution real-time image of When DSCOVR, or better, gets installed, with ocean experiments and then scaled the sunlit side of our planet. The camera the most important global activity it can up. And a sun-shield disk that can expand would reside at Lagrange-1, the point monitor will take place at the scale of a to a diameter of 2 kilometres would allow between the Sun and Earth where the bacterial gene. Metagenomics is giving heat-budget changes to be studied with gravitational pull is neutral. At this point in us detailed access to the genes and gene precision. space, 1.5 million kilometres from Earth, communities of bacteria and archaea, 99% DSCOVR equipped with a variable an object orbits the Sun in synchrony of which can’t be cultured in the lab. For sunshade could even act as a planetary with us. Gore’s scheme was modified and instance, analysis is revealing whole new thermo stat, making fine adjustments in the eventually named the Deep Space Climate metabolic pathways for oxygen and carbon amount of solar energy reaching Earth so Observatory (DSCOVR). This project won production by the ocean’s microbes. that a stable climate regime is maintained. approval from the US National Academy These pathways must be understood, This vision requires much better under- of Sciences and $100 million from the because their effects work on the planetary standing of temporal and regional energy US Congress, and the satellite was built. scale and could be harnessed as new energy budgets and their interplay with microbial DSCOVR’s positioning, between the sources. For example, the carbon tightly life on Earth. Sun and Earth, was to make it perfect for bound in lignin is broken down largely in A unifying body of data, ideas, models monitoring the planet’s albedo, the amount the microbial soup of termite hindguts. and images of the whole-Earth system could of light Earth reflects. This information Half of the world’s oxygen is produced by inspire the public and may shift scientific is crucial for improving climate models. ocean microbes, and they fix an unknown, thinking. In studying the energy dynamics The satellite was also to gauge Earth’s total but presumably enormous, amount of of the Earth–Sun system while learning how heat budget, measuring and guiding our atmospheric carbon. Once ecologists open our microbial partners manage to keep this progress in heading off global warming. It microbial black boxes such as the soil and planet comfortably terraformed for life, we was also to provide much-needed calibra- gut, and when they understand the prolific would begin to step up to the full meaning tion of the temperature readings from low transfer of genes between prokaryotes and of Earth stewardship. ■ Earth-orbiting satellites. And everyone with viruses, we will begin to comprehend the Stewart Brand founded and edited the a computer screen would have been able to extremely local interactions that take place Whole Earth Catalog. He is president of the contemplate the bracingly real ‘big here within a biological neighbourhood. With Long Now Foundation, co-founder of Global right now’ image of our planet. Sadly, the the kind of close monitoring that meta- Business Network. His next book, Whole Earth satellite languishes in a warehouse outside genomics offers, predictability of ecology Discipline: An Ecopragmatist Manifesto, will be Washington DC. The Bush administration should improve. published in late 2008 by Viking-Penguin. mothballed the project in January 2001, and This, perhaps, could be followed by cancelled hopes for its launch in 2006. engineering. To control global warming, FURTHER READING Whether or not DSCOVR makes it to we may one day resort to palliatives, such Handelsman, J. et al. The New Science of Metagenomics: Lagrange-1, something similar surely as a variable sunshade for Earth located at Revealing the Secrets of Our Microbial Planet (Natl Acad. must, and soon. We need to answer some Lagrange-1 or increasing the activity of Sci., Washinghton DC, 2007); www.nap.edu/catalog. php?record_id=11902. crucial questions. Where exactly does solar phyto plankton with deep-water nutrients NASA Deep Space Climate Observatory http://science. energy go when it hits Earth? How much of or iron. hq.nasa.gov/missions/satellite_53.htm it is absorbed by biological organisms? And Both routes offer the ability to manipu- Valero, F. DSCOVR Mission Summary http://cloud.ucsd. edu/dscovr/mission_summary.html how does biological life affect the physical late energy at the planetary scale, and each Karl, D. M. Nature 415, 590–591 (2002). energy flows in the atmosphere and oceans should be investigated incrementally. Solar Warnecke, F. et al. Nature 450, 560–565 (2007). ESSAY 797