The ABCs of Climate Change

Content provided by the Sierra Club.

We’ve put together these basic frequently asked questions to give you a starting point in your global warming education. When you’re done reading up on the basics, check out our site to learn more about how you can do your part to lower your contribution to global warming.

What causes global warming? Is it part of a natural cycle?

ABCs of Climate Change

Global warming is caused by the atmospheric buildup of greenhouse gases such as carbon dioxide and methane, which form a sort of blanket over the Earth, trapping in heat that would normally escape the atmosphere. Most human-generated greenhouse gases come in the form of carbon dioxide, a pollutant emitted from the burning of fossil fuels, such as coal, oil, and natural gas. While it is true that there has always been some natural climate variability, record levels of carbon dioxide are spurring far-reaching changes in our weather, sea levels, and climate. 

Throughout ice ages, higher concentrations of carbon dioxide have correlated with higher temperatures. Humans are exacerbating global temperatures through industrial activity which dramatically increases carbon dioxide concentrations in the atmosphere. In its recent report, the Intergovernmental Panel on Climate Change found that 2005 carbon dioxide levels significantly exceed average concentration levels over the past 650,000 years.

How can global warming affect our lives?

We do not yet fully know how radical climate change will affect our way of life, but we do know that the effects of growing carbon dioxide emissions already occurring are staggering: the eleven years ranging between 1995 and 2006 rank among the twelve warmest years recorded since 1850. Sea level rise will likely increase 20-50 inches (.5-1.4 meters) above 1990 levels by 2100, dramatically altering coastal communities and natural habitats.

Leading scientists assert that a rise of 2 degrees Celsius (4 degrees Fahrenheit) over pre-industrial temperatures would leave hundreds of millions of people around the world “exposed to increased water stress,” decrease air quality in cities, increase ocean acidification leading to the destruction of calcifying marine life (including coral and dependent species), negatively impact farmers and fishers, increase the likelihood and severity of wildfires, and dramatically escalate mortality rates resulting from drought, floods, and heat waves. Few ecosystems could adapt to such a dramatic temperature change, potentially resulting in the extinction of 30% of species and the loss of 30% of coastal wetlands. In North America specifically, higher temperatures will decrease snow pack in the western mountains, reducing summer water supplies and exacerbating chances of drought.

To avoid such catastrophes, scientists say that we must reduce our carbon emissions by at least 80% by 2050 to prevent global temperatures from rising above 2 degrees Celsius (4 degrees Fahrenheit) over pre-industrial averages.

Read the IPCC’s definitive report on the possible impacts of global warming.

Does the rise in Earth’s temperature cause more intense storms and hurricanes? If so, how?

Yes. Hurricanes are powered by warm water on the surface of the ocean. As global warming heats the surface of the water, hurricanes will increase in speed, power, and severity.

In its most recent report, IPCC found that tropical storms have become more intense in the North Atlantic since 1970, during which time period carbon dioxide levels have increased by 80%. The report also found that future tropical typhoons and hurricanes will likely become more intense as measured by higher wind speeds and heavier precipitation. More powerful cyclones will lead to crop damage, power outages, increase risk of food and water-borne diseases, population migration, and property loss.

What are the largest sources of global warming pollution in the world and in the United States?

According to 2005 figures by the Department of Energy, the US produces 21.1% of all CO2 emitted into the atmosphere, at 5,957 million metric tons. While it was second to the U.S. in 2005, China took over first place in mid-2007, emitting roughly 28% of the world’s CO2. But that does mean that the U.S. emits more CO2 than India (4.1%), Russia (6%), Japan (4.4%), Australia (1.4%), and more than all of Europe (16.6%).

The U.S. emits roughly 30% of its carbon dioxide from the transportation sector and 40% from power plants. We burn coal and natural gas to produce electricity for our homes, businesses, and factories. Most of the oil is burned to power transportation–planes, buses, and cars. Unfortunately, nearly all of the technology that produces this energy is outdated and inefficient. We can continue to live our lives by putting more efficient technology to use, and by generating more energy from clean sources like wind, solar and fuel cells.

Can we curb our emissions of global warming pollution without hurting our economy?

clean air

Absolutely. America’s current energy policy is terribly expensive, requiring large subsidies while taking a heavy toll on consumers. Studies show that by investing in clean, renewable energy and energy efficiency, we can reduce our greenhouse emissions the necessary 80% by 2050 while creating new jobs and saving consumers money, and we can do so without producing dangerous and expensive electricity from nuclear reactors.

While many countries in Europe and Asia are recognizing the need to curb emissions, America’s industries are falling behind. America needs policies and programs that will stimulate green power industries so we can ensure that America will once again lead the world in technology and manufacturing. And by making simple choices in the kinds of products we buy, such as compact florescent light bulbs and hybrid cars, we can all save money and protect the environment by consuming less energy.

How is the international community addressing climate change?

international community actions on global warming

Recognizing the urgency of the threat posed by climate change, developing countries agreed at recent UN climate change negotiations in Bali to complement developed-country mitigation targets with nationally appropriate mitigation actions of their own. This represents a significant change of position on the part of developing countries. The U.S. has the opportunity to capitalize on the momentum of Bali if we act quickly to put in place the necessary legislation to reduce domestic emissions.


Is it too late to stop global warming?

While it is true that global warming is already occurring and affecting the way we live, we can prevent global temperatures from reaching dangerous levels if we take steps now to begin dramatically reducing our carbon emissions. If we do not begin to shift to clean energy, the heat waves and hurricanes that we have already suffered through will worsen. Thankfully, we have all the tools necessary to curb our emissions of greenhouse gases–tools like clean energy, energy efficiency, and cars that go farther on a gallon of gas. Click here to learn more about global warming solutions.


  1. Jerry October 16, 2009
  2. Edison October 24, 2010

Add Comment

Art and Design Energy Star Green News Insider Interviews Lifestyle Success Stories Travel Videos
How to Choose the Right Light Bulb for Your Home
Water, Water Everywhere, Nor Any Drop to Drink….
A New Champion At The Weather Channel Answers All You Want To Know About The Weather But Were Afraid To Ask
Air sealing Apparel Appliances Bath Bed Body Care Books and DVDs Cabinets Children and babies Cleaning Composting Countertops Dry cleaning Electronics Energy Auditors and Home Performance Contractors Flooring Food Furniture Heating Ventilation Air Conditioning (HVAC) Holiday Home renovation helpers Home safety products Indoor Air Quality Insulation Landscaping and outdoors Lighting Lumber and panel products Miscellaneous Paints Finishes and Adhesives Passive Solar Personal Care Pest control (indoors) Pets Recycling Renewable energy Roofing products Siding Solar Transportation Waste Water Water fixtures and plumbing Windows skylights and doors
How to Choose the Right Light Bulb for Your Home
Water, Water Everywhere, Nor Any Drop to Drink….
Squeezing Water From A Rock