Predictions

The ability to make good forecasts, aided by the use of satellites, is critical for human well-being.

Weather Forecasting

The world operates a range of weather satellites. Around polar orbit are the Television Infrared Observation Satellite (TIROS) series, followed by the Polar-orbiting Operational Environmental Satellites (POES) series, as well as the Search and Rescue Satellite-Aided Tracking system (SARSAT) for search and rescue. In geosynchronous orbit is the Geostationary Operational Environmental Satellite (GOES) series, which continues to be developed ¹.

The World Bank estimates that weather forecasting, of which weather satellites are a major component, generates $162 billion per year in socioeconomic value ². They furthermore found that further investments carry a cost-benefit ratio of at least 3:1, meaning that they generate at least $3 in value for each $1 spent ². Additionally, 23,000 lives per year could be saved by upgrading early warning weather systems around the world to standards now enjoyed in Europe ².

Climate Modeling

Satellites have been invaluable for monitoring longer-term climate changes, including concentrations of carbon dioxide and other greenhouse gases, sea ice development, deforestation, and land use change ³.

Asteroid Impact

A large asteroid impact, though unlikely, could be a catastrophic event. As of September 2021, the last asteroid impact to do significant damage was the 2013 Chelybinsk impact, which caused 1600 injuries ⁴. The much larger Tunguska impact of 1908 would have had devastating effect if it has hit in a populated area ⁵. NASA estimates the risk of asteroid impacts as follows.

Source: NASA ⁶.

Efforts are ongoing to detect potentially threatening near Earth asteroids by ground- or space-based telescopes. So far, most of only the most threatening class of asteroids have been found.

NASA's search for civilization-threatening asteroids is proceeding, but fewer potentially dangerous classes, such as the Tunguska impactor (about 50 meters) or the Chelybinsk impactor (about 20 meters) are known. Sources: Wall ⁷⁸ and NASA ⁹. It is not feasible to find 100% of even large potential impactors, and thus the threat of an unexpected impact cannot be eliminated entirely ¹⁰.

If an asteroid with high risk of impact with Earth is found, it can be deflected or destroyed with nuclear devices, kinetic energy such as from striking it with a spacecraft, or momentum imparted by solar sails ¹¹. It may require 5-10 years to conduct a successful deflection mission ¹². No such mission has yet been demonstrated.

NASA's budget for planetary defense (asteroid detection and impact mitigation) was about $150 million each for Fiscal Years 2018 and 2019 ¹³.

Solar Storms

The most severe solar storm known in history was the Carrington Event of 1859, which disrupted telegraphs and causes auroras to be visible throughout most of the world. If a similar event happened today, damages could be in the trillions of dollars ¹⁴. The likelihood of such storms is uncertain but estimated as follows.

The severity of geomagnetic storms is often measured in Dst (disturbance – storm time), a measure of the change of magnetic field. The figures are typically in nanoteslas (nT). In a quiet period, the disturbance is typically between -20 nT and +20 nT. Sources: ¹⁵ and ¹⁶. Separately, the risk of an event at least as severe as the Carrington Event has been estimated at 12% over a decade ¹⁷, or 0.46-1.88% over a decade ¹⁸.

The European Space Agency and the National Aeronautics and Space Administration (NASA) operate the Solar and Heliospheric Observatory (SOHO) and other space- and ground-based space weather monitors that will give us a few hours, or a day or two, of advance warning in the event of a geomagnetic storm ¹⁹. Advance warning gives power grid operators time to shut off and harden vulnerable components ²⁰.

It has been proposed that the U. S. Federal Government establish a strategic reserve of transformers and mobile substations to mitigate against a severe geomagnetic storm or an electromagnetic pulse (EMP) attack, but this has not been found to be cost-effective ²¹.