Malaspina Glacier, Alaska

© Copyright 2008 Monique Romeijn/Impressions of Earth. All Rights Reserved.

Since 1990’s a new generation of satellite sensors with powerful capabilities have been launched to collect massive amounts of data about our planet and the many changes it has experienced.

Satellite images have been collected for scientific and technical purposes as well as just appreciating its simple beauty. These satellites collect information that our eyes cannot. There are dozens of remote sensing satellites orbiting the Earth collecting invaluable information about the Earth’s surface, oceans and the atmosphere and how they interact.

Satellite images provide important land coverage information for mapping and classification of land cover features, such as vegetation, soil, water and forests for monitoring and managing Earth’s vital natural resources and the current global climate changes.

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Global Climate Change

The Earth’s climate has changed throughout history. From glacial periods (or “ice ages”) where ice covered significant portions of the Earth to interglacial periods where ice retreated to the poles or melted entirely – the climate has continuously changed.

Malaspina Glacier, Alaska

The shallow end of this Glacier is melting swiftly. Glaciologists have determined that areas of the glacial lobe were 98 feet lower in 2004 than they were in 2000. That’s double the rate of pre-1999 thinning.

The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.

Scientists have been able to piece together a picture of the Earth’s climate dating back decades to millions of years ago by analyzing a number of surrogate, or “proxy,” measures of climate such as ice cores, boreholes, tree rings, glacier lengths, pollen remains, and ocean sediments, and by studying changes in the Earth’s orbit around the sun.

Since the Industrial Revolution (around 1750), human activities have substantially added to the amount of heat-trapping greenhouse gases in the atmosphere. The burning of fossil fuels and biomass (living matter such as vegetation) has also resulted in emissions of aerosols that absorb and emit heat, and reflect light.

The addition of greenhouse gases and aerosols has changed the composition of the atmosphere. The changes in the atmosphere have likely influenced temperature, precipitation, storms and sea level. However, these features of the climate also vary naturally, so determining what fraction of climate changes are due to natural variability versus human activities is challenging.

Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. Studying this data collected over many years reveal the signals of a changing climate.

Greenhouse gas concentrations in the atmosphere will increase during the next century unless greenhouse gas emissions decrease substantially from present levels. Increased greenhouse gas concentrations are very likely to raise the Earth’s average temperature, influence precipitation and some storm patterns as well as raise sea levels. The magnitude of these changes, however, is uncertain.

More Resources on Earth Observation::

NASA Web Site on Global Climate Change – A Web site from NASA’s Jet Propulsion Laboratory devoted to educating the public about Earth’s changing climate. The Global Climate Change Web site provides easy-to-understand information about the causes and effects of climate change and how NASA studies it.

Book of NASA Satellite Imagery of Global Climate Change: http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/data_products/ourchangingplanet.php

Earth Sciences Portal: http://earthsciencesportal.gsfc.nasa.gov/

Satellite Tracker: http://orbits.eoportal.org/

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