Global Warming 101 | National Geographic

for 2.5 million years the Earth’s

for 2.5 million years the Earth’s climate has fluctuated cycling from ice

climate has fluctuated cycling from ice

climate has fluctuated cycling from ice ages to warmer periods but in the last

ages to warmer periods but in the last

ages to warmer periods but in the last century the planets temperature has

century the planets temperature has

century the planets temperature has risen unusually fast about 1.2 to 1.4

risen unusually fast about 1.2 to 1.4

risen unusually fast about 1.2 to 1.4 degrees Fahrenheit scientists believe

degrees Fahrenheit scientists believe

degrees Fahrenheit scientists believe it’s human activity that’s driving the

it’s human activity that’s driving the

it’s human activity that’s driving the temperatures up a process known as

temperatures up a process known as

temperatures up a process known as global warming

global warming

global warming ever since the industrial revolution

ever since the industrial revolution

ever since the industrial revolution began factories power plants and

began factories power plants and

began factories power plants and eventually cars have burned fossil fuels

eventually cars have burned fossil fuels

eventually cars have burned fossil fuels such as oil and pole releasing huge

such as oil and pole releasing huge

such as oil and pole releasing huge amounts of carbon dioxide and other

amounts of carbon dioxide and other

amounts of carbon dioxide and other gases into the atmosphere these

gases into the atmosphere these

gases into the atmosphere these greenhouse gases trap heat near the

greenhouse gases trap heat near the

greenhouse gases trap heat near the earth through a naturally occurring

earth through a naturally occurring

earth through a naturally occurring process called the greenhouse effect the

process called the greenhouse effect the

process called the greenhouse effect the greenhouse effect begins with the Sun

greenhouse effect begins with the Sun

greenhouse effect begins with the Sun and the energy it radiates to the earth

and the energy it radiates to the earth

and the energy it radiates to the earth the earth and the atmosphere absorbs

the earth and the atmosphere absorbs

the earth and the atmosphere absorbs some of this energy while the rest is

some of this energy while the rest is

some of this energy while the rest is radiated back into space

radiated back into space

radiated back into space naturally-occurring gases in the

naturally-occurring gases in the

naturally-occurring gases in the atmosphere trap some of this energy and

atmosphere trap some of this energy and

atmosphere trap some of this energy and reflected back warming the earth

reflected back warming the earth

reflected back warming the earth scientists now believe that the

scientists now believe that the

scientists now believe that the greenhouse effect is being intensified

greenhouse effect is being intensified

greenhouse effect is being intensified by the extra greenhouse gases that

by the extra greenhouse gases that

by the extra greenhouse gases that humans have released evidence for global

humans have released evidence for global

humans have released evidence for global warming includes a recent string of very

warming includes a recent string of very

warming includes a recent string of very warm years scientists report that 1998

warm years scientists report that 1998

warm years scientists report that 1998 was the warmest year in measured history

was the warmest year in measured history

was the warmest year in measured history with 2005 coming in second meanwhile

with 2005 coming in second meanwhile

with 2005 coming in second meanwhile readings taken from ice cores show that

readings taken from ice cores show that

readings taken from ice cores show that the greenhouse gases carbon dioxide and

the greenhouse gases carbon dioxide and

the greenhouse gases carbon dioxide and methane have hit their highest levels in

methane have hit their highest levels in

methane have hit their highest levels in the past 420 thousand years

the past 420 thousand years

the past 420 thousand years Arctic sea ice is also shrinking

Arctic sea ice is also shrinking

Arctic sea ice is also shrinking according to NASA studies the extent of

according to NASA studies the extent of

according to NASA studies the extent of Arctic sea ice has declined about 10

Arctic sea ice has declined about 10

Arctic sea ice has declined about 10 percent in the last 30 years as long as

percent in the last 30 years as long as

percent in the last 30 years as long as industrialized nations consume energy

industrialized nations consume energy

industrialized nations consume energy and developing countries increase their

and developing countries increase their

and developing countries increase their fossil fuel consumption the

fossil fuel consumption the

fossil fuel consumption the concentration of greenhouse gases in the

concentration of greenhouse gases in the

concentration of greenhouse gases in the atmosphere will continue to rise

atmosphere will continue to rise

atmosphere will continue to rise researchers predict that temperatures

researchers predict that temperatures

researchers predict that temperatures will increase about two to 10 degrees

will increase about two to 10 degrees

will increase about two to 10 degrees Fahrenheit by the end of the century

Fahrenheit by the end of the century

Fahrenheit by the end of the century what’s less certain is what rising

what’s less certain is what rising

what’s less certain is what rising temperatures mean for the planet some

temperatures mean for the planet some

temperatures mean for the planet some climate models predict subtle changes

climate models predict subtle changes

climate models predict subtle changes others forecast rising sea levels which

others forecast rising sea levels which

others forecast rising sea levels which could flood coastal areas around the

could flood coastal areas around the

could flood coastal areas around the world weather patterns could change

world weather patterns could change

world weather patterns could change making hurricanes more frequent severe

making hurricanes more frequent severe

making hurricanes more frequent severe droughts could become more common in

droughts could become more common in

droughts could become more common in warm areas and species unable to adapt

warm areas and species unable to adapt

warm areas and species unable to adapt to the changing conditions would face

to the changing conditions would face

to the changing conditions would face extinction although much remains to be

extinction although much remains to be

extinction although much remains to be learned about global warming

learned about global warming

learned about global warming many organizations advocate cutting

many organizations advocate cutting

many organizations advocate cutting greenhouse gas emissions to reduce the

greenhouse gas emissions to reduce the

greenhouse gas emissions to reduce the impact of global warming

impact of global warming

impact of global warming consumers can help by saving energy

consumers can help by saving energy

consumers can help by saving energy around the house switching to compact

around the house switching to compact

around the house switching to compact fluorescent light bulbs and driving

fluorescent light bulbs and driving

fluorescent light bulbs and driving fewer miles in the car each week these

fewer miles in the car each week these

fewer miles in the car each week these simple changes may help keep the earth

simple changes may help keep the earth

simple changes may help keep the earth cooler in the future

cooler in the future

cooler in the future [Music]