The Facts About Climate Change

The climate on earth is changing. So what's the big deal?

Climate has historically changed, from Ice Ages to warming periods. Scientists currently have climate data that go back nearly 400,000 years, and as technology improves, so does the accuracy of the data. Global circulation models (GCM) help scientists to test and confirm the data and predict the effects of climatic change, and those models, once primitive and inaccurate, are rapidly improving in their ability to inform us.

The real problem facing us now is that the changes in climate currently being observed do not fit into the pattern of historical variation. Instead, we are seeing unprecedented changes, outside the historic range of climactic factors, and while some parts of the puzzle are still uncertain, what is certain is that the world we live in is dramatically changing.

How do we know climate change is real?

The Intergovernmental Panel on Climate Change (IPCC) is a consortium of leading scientists in a wide range of climate-related subjects from nations all around the world. The IPCC's latest report in 2007 declared: "Warming of the climate system is now unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level." The authors continue to assert that with 90 percent certainty, most of the observed increase in global average temperatures since the mid-20th century is due to the observed increased in manmade greenhouse gas concentrations.

Unprecedented levels of greenhouse gases are being released by human activity and altering the earth's climate.¹ Carbon dioxide levels are higher today than they have been in 800,000 years.² Over the course of the past 400,000 years, the level of carbon dioxide in the earth's atmosphere has fluctuated, never falling below 180 parts per million and never rising above 300. Since the mid 1800s, however, the concentration of carbon dioxide in the atmosphere has skyrocketed to 380 parts per million. Both the speed and magnitude of the present increase in carbon dioxide levels are unprecedented and are directly attributable to humanity's use of natural resources since the Industrial Revolution.³

What other changes are occurring? The Arctic ice cap is shrinking by nine percent every year, and the past two decades have seen eighteen of the warmest years on record. In the past thirty years, the number of category 4 and 5 hurricanes has doubled and extremely dry land area has doubled.⁴ Extreme weather events displace populations and impair crucial infrastructure, such as waterways, agricultural land, and hospitals. Sea level, which is rising now for the first time since the last ice age 2000 years ago and is caused by melting ice on land and water's expansion at higher temperatures, will damage coastal regions and communities.⁵ Extreme weather and climatic shifts can be disastrous for infrastructure, alters agricultural productivity, and spreads disease to new regions.These are just a few of the observations that serve as evidence for climate change. We encourage and invite you to visit the IPCC website to learn more from the world's top scientists.

Though the consequences of global warming are not yet fully understood, these scientists are working to illuminate the problem. We know that the severity of future effects depends a great deal on mitigation in the present and we know that the current global trends in extreme weather can be explained by the enhanced greenhouse effect. Dry areas are getting dryer and wet areas are getting wetter. Storms, floods, droughts, and heat waves are becoming more intense and more frequent.⁶

Our world is changing, and with it, so will our lives.

In fact, a collaborative report on the effects of climate change on health from The Lancet medical journal and the UK-based University College London, published on May 14th⁷, concludes that climate change is a health problem, not just an environmental issue. The report outlines the main threats to health from climate change: changing patterns of disease and mortality; food, water and sanitation; vulnerable shelter and human settlements; and increased extreme events and migration. The authors write that poorer countries are going to see the greatest effects of climate change, as these nations lack essential information about their vulnerability to climate change and lack the resources necessary to respond.

The dangers to public health confronting humans will also affect biodiversity: more extreme temperatures, storms, and sea level rise will disrupt habitats worldwide. Current warming is forcing ecosystems farther towards the poles or higher up in altitude, which affects species' survival by diminishing their habitat or causing it to change too quickly.⁸ Already, at least 279 species have migrated further towards the poles.⁹ A global temperature increase of 2 degrees will put 30 percent of the world's species at risk of extinction.

If this is all true, why do some people say climate change isn't a problem?

Because global climate is such a complex system with many various factors acting at the local, regional and global scale, it is very difficult to predict outcomes because there are so many different ways these factors can behave and interact. Furthermore, not all observations will be consistent with a global warming trend because of local factors and interactions. Plus, it takes a long time for the effects of climate change to accumulate into noticeable change, so while climate is and has been changing, many of the dramatic changes are yet to come.

Think of watching the weather for one day in your hometown. It may be sunny and warm, but maybe it's above average temperature that particular day. Maybe it's below average temperature. And maybe a big storm is brewing to the west and hasn't reached your town yet, so you don't know that in two days it will be rainy and windy. Plus, based on that day alone, you won't know what the weather will be like in two years, or five years, or ten years, or whether it's been getting colder or warmer. That's because local measurements reflect local conditions and interactions, not trends that occur over large spatial areas over a long period of time.

There will be a great deal of variation across the globe, and not all observations will fit the pattern, but there is a pattern, and the evidence is mounting. The world's climate is changing, and we will have to change our lives with it.

What can we do about increased atmospheric carbon dioxide?

Energy production through the burning of coal, natural gas, and oil is the number one source of greenhouse gas emissions, releasing trillions of tons of carbon dioxide into the atmosphere every year. Before human activity began freeing the carbon stored in fossil fuels and vegetation, there was a balanced exchange of CO₂ between the atmosphere, the biosphere, and the oceans; major climatic shifts were caused by variations in volcanic activity and solar radiation. Now, however, human-driven emissions serve to enhance the insulating capacity of the atmosphere, making the earth warmer than it would otherwise be.

Reducing your energy consumption or switching to renewable sources of energy can dramatically lower your carbon emissions - and save you money! Visit our Take Action section to discover simple and easy ways you can combat climate change by saving energy.

EcoLogic is working to address climate change through carbon sequestration, or the capture and storage of carbon dioxide from the atmosphere. Twenty percent of global carbon dioxide emissions come from deforestation, and EcoLogic aims to address this problem while simultaneously protecting biodiversity and ensuring sustainable livelihoods in rural communities of Central America. EcoLogic works with community-based organizations to plant new trees and restore existing forests, alleviating damage from deforestation and offsetting carbon emissions. Read more about our work to protect the world's natural carbon storage facilities: forests!

By The Numbers

Greenhouse Gases and Human Activity

Human activities cause the release of greenhouse gases
Carbon dioxide levels in the atmosphere are higher today than they have been in 800,000 years
Increases in the concentration of the greenhouse gases CO₂, methane, nitrous oxide, and halocarbons are attributable to human activity since industrialization
If no action is taken to abate global warming, the United States will experience up to 12.6°F of warming
75% of human-driven CO₂ emissions come from the burning of fossil fuels for energy
33% of human-driven CO₂ emissions come from the transportation sector
Tropical deforestation accounts for 20% of global CO₂ emissions
The Arctic icecap is declining at a rate of 9% per year
The United States has one twentieth of the world's population, who release one fifth of the world's greenhouse gases
One third of all the CO₂ released by human activity since 1850 has been released by the United States
Americans release 20 tons of CO₂ per person per year, two times the European average and four times the global average
Coal burning power plants in the US release 2.5 billion tons of CO₂ per year, automobiles release 1.5 billion tons
The closest earth has come to the current CO₂ concentration during the past 400 millennia was 320,000 years ago, when the closest relatives to modern humans were the early Neanderthals, and even then CO₂ was only 300 ppm.

Public Health

Global climate change will lead to more frequent and more severe extreme weather events such as hurricanes, droughts, heat waves, tropical storms, and flooding
A rise in sea level of 16 inches could put up 125 million people at risk for flooding
Land areas defined as "very dry" have doubled in extent since the 1970s
50% of the US population lives near the coast and is therefore vulnerable to sea level rise/ocean effects of climate change
Over 30,000 people were killed in the 2003 heat wave in Europe, which was the worst in 500 years
The Midwest has seen two severe floods of the intensity expected only once every hundred years, in the past 15 years
Category 4 and 5 storms have doubled in the past thirty years

Ecosystems

Climate change could become the main driver of species extinction by the end of the century
An average increase of 2 degrees F will put up to 30 percent of the world's species at risk for extinction