Afia Mushtaq Bhatti
The Earth’s climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives. With rapid climate change, one-fourth of Earth’s species could be headed for extinction by 2050. The United States Global Change Research Program (which includes the Department of Defense, NASA, National Science Foundation and other government agencies) has said that “Global warming is unequivocal and primarily human-induced and climate changes are underway in the United States and are projected to grow” In addition to impacting our water resources, energy supply, transportation, agriculture, and ecosystems, the United States Global Change Research Program concludes that climate change Carbon dioxide and other global warming pollutants are collecting in the atmosphere like a thickening blanket, trapping the sun’s heat and causing the planet to warm up.
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 these climate data collected over many years reveal the signals of a changing climate. Although local temperatures fluctuate naturally, over the past 50 years the average global temperature has increased at the fastest rate in recorded history. Scientists say that unless we curb the emissions that cause climate change, average U.S. temperatures could be 3 to 9 degrees higher by the end of the century.
The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century. Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response. Ice cores drawn from Greenland, Antarctica, and Tropical Mountain glaciers show that the Earth’s climate responds to changes in greenhouse gas levels. They also show that in the past, large changes in climate have happened very quickly, geologically-speaking: in tens of years, not in millions or even thousands.
* Global sea level rose about 17 centimeters (6.7 inches) in the last century. The rate in the last decade, however, is nearly double that of the last century.
* The major global surface temperature reconstructions show that Earth has warmed since 1880. Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years. Even though the 2000s witnessed a solar output decline resulting in an unusually deep solar minimum in 2007-2009, surface temperatures continue to increase.
* The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.8
* The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA’s Gravity Recovery and Climate Experiment show Greenland lost 150 to 250 cubic kilometers (36 to 60 cubic miles) of ice per year between 2002 and 2006, while Antarctica lost about 152 cubic kilometers (36 cubic miles) of ice between 2002 and 2005.
* Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.
* Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.
* The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.
* Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent. This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.
* Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier.
With current technology, renewable energy sources like wind, solar, and geothermal can provide 96% of our electricity and 98% of our total heating demand — accounting for almost all of our primary energy demand. Investing in renewable could jumpstart our flagging economy, creating millions of jobs that can’t be shipped overseas. The first challenge is eliminating the burning of coal, oil and, eventually, natural gas. Pick a Green-e-certified energy supplier that generates at least half of its power from wind, solar energy and other clean sources. Replace your light bulbs with compact fluorescent bulbs. Compact fluorescent bulbs (CFLs) last 10 times longer than incandescent bulbs. What’s more, CFLs lower your energy bills and keep a half-ton of carbon dioxide out of the air. Buildings worldwide contribute around one third of all greenhouse gas emissions even though investing in thicker insulation and other cost-effective, temperature-regulating steps can save money in the long run. Heating and cooling consume about 40 percent of energy in the home. Sealing drafts and making sure that your home has adequate insulation are two easy ways to become more energy-efficient. The easiest way to cut back on greenhouse gas emissions is simply to buy less stuff. Whether by forgoing an automobile or employing a reusable grocery sack, cutting back on consumption results in fewer fossil fuels being burned to extract, produce and ship products around the globe Choose an efficient vehicle: High-mileage cars such as hybrids and plug-in hybrids use less gas and save money. Or more advisably, Choose alternatives to driving such as public transit, biking, walking and carpooling, and bundle your errands to make fewer trips. Improved agricultural practices along with paper recycling and forest management—balancing the amount of wood taken out with the amount of new trees growing—could quickly eliminate this significant chunk of emissions.