Section 2: Climate Change
This needs a lot more footnoting. I will fill that in later. -Jessie
The Earth’s weather patterns have changed over the course of the planet’s history.
Glaciers form and melt, rivers filled with rainwater come and go, and heat waves roll across the
globe. Today, the Earth’s climate is continuing to change and changing rapidly. Atmospheric
gasses that insulate the Earth have historically helped maintain a comfortable life-supporting
average temperature of 59 degrees Fahrenheit.1 Recent evidence indicates, however, that now
the earth’s atmosphere is doing the insulation job a little too well.
Greenhouse gasses – water vapor and much smaller amounts of carbon dioxide, methane,
and nitrous oxide – act as a thermal blanket for the Earth, keeping some of the sun’s infrared
radiation from radiating back into space. This creates a climate that supports life as we know it.
As carbon dioxide and other greenhouse gasses increase in the atmosphere, the composition of
the Earth’s natural thermal atmospheric blanket changes. It grows thicker. The thick atmosphere
traps an ever-higher amount of infrared radiation inside the atmosphere. A growing body of
evidence from around the world indicates that this change in the atmosphere is changing, and
will continue to change, climates around the globe, causing the ice caps to melt a little more each
year, and rain and drought patterns to shift from historic norms.
A large body of scientific evidence indicates that the world’s climate has seen an increase
in carbon dioxide, a key component of the thermal blanket. One of the longest running projects
to measure carbon dioxide concentrations was started in 1958 in Hawaii The measurements have
shown a steady increase in carbon dioxide concentrations. Pre-industrial carbon dioxide levels in
Hawaii were 280 parts per million. In 2005, the concentration measured in Hawaii was 381 parts
per million. Scientist have determined through studying ice core samples taken in Greenland and
Antarctica, that in the past 650,000 years atmospheric carbon dioxide levels never went over 300
parts per million. It is estimated that by the 2013, carbon dioxide levels will exceed 400 parts per
million2. Levels below 350 parts per million are generally considered safe. We have passed that
level already and are continuously adding more carbon dioxide. This puts us on a path of largescale disruptions in nature, food and water that is already affecting peoples and communities
around the world.
As carbon dioxide levels rise, temperatures rise. Scientists estimate that a doubling of
greenhouse gas concentrations in the atmosphere could result in a global temperature increase of
3.6 to 8 degrees Fahrenheit.3 Scientists have measured temperatures back to the year 1000 by
measuring amounts of oxygen in ice core samples from around the world.4 We now know that
global temperatures were warmer from 1000 to 1400 than from 1400 to 1900. Some mainstream
media articles have pointed to this cyclical temperature change as an indicator that temperature
changes are natural and not driven by humanity's industrial activities. But by the year 2000,
temperatures were three times hotter than the warmest temperatures occurring since the year
1
2
3
4
http://climate.nasa.gov/causes/
For current carbon dioxide levels in the atmosphere: http://co2now.org/
1000. Of the 21 warmest years after 1860, 20 of them were after 1980. Average global
temperatures have climbed 1.4 degrees Fahrenheit since 1880.5 The planet is now hotter than
anytime in the past 1000 years, and increasing carbon dioxide levels indicate that it's only going
to get hotter.
Human activities have dramatically increased the amount of greenhouse gasses that are
emitted into the atmosphere. This is what is causing global warming. Most respected scientific
bodies, both nationally and internationally, have come to this conclusion.6 928 articles were
published in peer-reviewed journals on climate change between 1996 and 2006. None of those
articles concluded that this current period of global warming is naturally occurring. The scientific
world is unified in its conclusion that human activities are causing global warming.7
We can already see the effects of global warming in our world through shrinking arctic
sea ice and glaciers, extreme weather, and disappearing habitat.8 Arctic ice is rapidly
disappearing, and the region may have its first completely ice-free summer by 2040 or earlier.9
Polar bears and indigenous cultures are already suffering from the sea-ice loss.10 In addition,
glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park
now has only 27 glaciers, versus 150 in 1910.11 In the Northern Hemisphere, thaws are coming a
week earlier in spring and freezes begin a week later.12 As the atmosphere warms, the oceans
warm. As the oceans warm, storms get stronger.13 Major storms in the Atlantic and the Pacific
have increased in intensity and duration by 50% since 1970. These changes in ocean
temperatures also threaten wildlife. Coral reefs, which are highly sensitive to small changes in
water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded
in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events
to increase in frequency and intensity in the next 50 years as sea temperatures rise.
5
NASA's Goddard Institute for Space Studies
One detailed study, “Expert Credibility in Climate Change,” published in the Proceedings of the National Academy
of Science, July 6, 2010, focused on 1,372 climate researchers and found that “97-98 percent of the climate
researchers most actively publishing in the field … supported the basic tenets of ACC (manmade global warming)
established by the Intergovernmental Panel on Climate Change.”
7
http://climate.nasa.gov/causes/;
http://www.sciencedaily.com/releases/2011/11/111103120223.htm;
http://www.noaanews.noaa.gov/stories2011/20111027_drought.html;
http://science.discovery.com/stories/week/human-caused-climate-change.html;
http://epa.gov/climatechange/indicators.html;
http://www.scientificamerican.com/article.cfm?id=three-quarters-of-climate
8
See National Geographic Global Warming Fast Facts at:
http://news.nationalgeographic.com/news/2004/12/1206_041206_global_warming.html
9
John Roach, Arctic Summers Ice Free by 2040, Study Predicts, National Geographic News,
December 12, 2006, http://news.nationalgeographic.com/news/2006/12/061212-arctic-ice.html.
10
Global Warming Changing Inuit Lands, Lives, Arctic Expedition Shows, Jon Bowermaster, National Geographic
News, May 15, 2007 http://news.nationalgeographic.com/news/2007/05/070515-inuit-arctic.html.
6
11
12
13
The results of global warming will be felt around the world. More than a million species
face extinction from disappearing habitat, changing ecosystems, and acidifying oceans. As
glaciers around the world melt, sea levels will rise and water shortages will occur in regions
dependent on glacier runoff for fresh water. Sea levels could rise between 7 and 23 inches by the
end of this century.14 Rises of just 4 inches could flood many South Seas islands and swamp
large parts of Southeast Asia. Some hundred million people live within 3 feet of mean sea level,
and much of the world's population is concentrated in vulnerable coastal cities. In the United
States, Louisiana and Florida are especially at risk. Strong hurricanes, droughts, heat waves,
wildfires, and other natural disasters may become commonplace in many parts of the world. The
growth of deserts may also cause food shortages in many places.
These changes are also impacting human society in a different way. Extensive periods of
drought impact agriculture in some regions, where other regions are more prone to bigger and
more frequent flooding. Globalization adds to the impact this has on poor communities over the
world as a result of rising food prices on the world market that are affected by failed crops. The
availability of fresh water is impacted in the same way. This makes sanitation issues all the more
complicated. We are in for a period where these distortions are getting more frequent and more
prolonged. In the West, we can pretend that this is not happening because for now we can buy
our way out of this. For now, although we all know that this is unsustainable by itself as well.
How to move forward? What can we learn from science about what matters most?
Perhaps a short review of the biggest sources of greenhouse gasses can help us.
It is important to know that emissions of greenhouse gasses do not only include carbon
dioxide. The main greenhouse gas is carbon dioxide, or CO2. Carbon dioxide is released when
we are burning fossil fuels such as oil, coal, gas and gasoline. These are all energy related.
Another greenhouse gas is methane, or natural gas, or CH4. This is what we use to heat our
homes and cook our food. A significant amount of methane is released by our livestock in our
feedlots. The top three is rounded of by the emission of laughing gas, or nitrous oxide, or N2O.
Most emissions of laughing gas are related to the production and use of fertilizers. These gasses
all have different lives in the atmosphere but most scenarios are focusing on their impact over a
period of 100 years. That is also important to know: nature does clean up, but it takes generations
and we have been adding more than nature can handle for a while.
If we look at the short term impact of greenhouses gasses emissions of particles and soot
are also relevant. These arise also from burning heavy fuels such as diesel and fuel oil. Picture
that truck on the highway and you know what we mean.
If you look at this list of emissions and the sources, you can start to see a way forward
that we can take to get us out of the woods. We need to start making better use of our energy
through conversation and energy efficiency. We need to make our energy from non-carbon based
fuels. You can think of renewable energy as wind and solar. And we need to transform the way
we make food, meat and goods and services in ways that use less fertilizers and is based on
sustainable agriculture and manufacturing. We need to prepare ourselves to become carbon
positive. There are many ways to start living a low carbon life that is joyful, inspiring and rich in
social context and relations.
14
IPCC's February 2007 report