Climate Change

Boldor Ioana

Global Warming

Climate Change

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 11,700 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.

FActs

ce cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly ten times faster than the average rate of ice-age-recovery warming. Carbon dioxide from human activity is increasing more than 250 times faster than it did from natural sources after the last Ice Age.3

The ability of carbon dioxide and other gases to influence the transmission of infrared energy through the atmosphere was demonstrated in the mid-19th century.2 It is the theoretical basis of many NASA instruments flown.There is no doubt that the levels of greenhouse gases would cause the Earth to warm.

Scientists have been able to see the big picture thanks to Earth-orbiting satellites and other technological advancements, which have enabled them to collect a wide range of data about our world and its environment on a global scale.The signs of a changing environment are revealed in this body of evidence, which has been gathered over several years.

Scientific evidence for warming of the climate system is unequivocal.

The current warming trend is noteworthy because the majority of it is highly likely (greater than 95 percent probability) to be the product of human activity since the mid-twentieth century, and it is occurring at an unparalleled pace over millennia.1

The planet's average surface temperature has risen about 2.12 degrees Fahrenheit (1.18 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide emissions into the atmosphere and other human activities.4 Most of the warming occurred in the past 40 years, with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the warmest year on record. 5

Global temperature rise

Shrinking Ice Sheets

Sea Levels rise

Ocean Warming

Global sea level rose about 8 inches (20 centimeters) in the last century. The rate in the last two decades, however, is nearly double that of the last century and accelerating slightly every year.10

The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost an average of 279 billion tons of ice per year between 1993 and 2019, while Antarctica lost about 148 billion tons of ice per year.7

The ocean has absorbed much of this increased heat, with the top 100 meters (about 328 feet) of ocean showing warming of more than 0.6 degrees Fahrenheit (0.33 degrees Celsius) since 1969.6 Earth stores 90% of the extra energy in the ocean.

Life on Earth depends on energy coming from the Sun. About half the light reaching Earth's atmosphere passes through the air and clouds to the surface, where it is absorbed and then radiated upward in the form of infrared heat. About 90 percent of this heat is then absorbed by the greenhouse gases and radiated back toward the surface.

we live in a green house

A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO2 concentration by 47% since the Industrial Revolution began. This is the most important long-lived "forcing" of climate change.

Carbon dioxide (CO2)

A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.

Water vapors

The most abundant greenhouse gas, but importantly, it acts as a feedback to the climate. Water vapor increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.

Nitrous oxide

Certain gases in the atmosphere block heat from escaping. Long-lived gases that remain semi-permanently in the atmosphere and do not respond physically or chemically to changes in temperature are described as "forcing" climate change. Gases that contribute to the greenhouse effect include:.

Causes

• Temperatures will continue to rise
• Frost-free Season (and Growing Season) will LengthenFrost-free Season (and Growing Season) will Lengthen
• Changes in Precipitation PatternsChanges in Precipitation Patterns
• More droughts and heat waves
• Hurricanes Will Become Stronger and More IntenseHurricanes Will Become Stronger and More Intense

Efects

Responding to climate change involves two possible approaches: reducing and stabilizing the levels of heat-trapping greenhouse gases in the atmosphere (“mitigation”) and/or adapting to the climate change already in the pipeline (“adaptation”). NASA's role is to make detailed climate data available to the global community, including the public, policy- and decision-makers, and scientific and planning agencies.

Solutions

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