Global Warming 101: Science, Sources, Solutions, and Impacts

A Safe Climate for All of Us

Everyone wants a safe world where we can enjoy a clean environment. The Safe Climate Campaign is working to solve the biggest challenge we face: Global warming. The technology exists today to protect our fragile climate by cutting our dependence on polluting fossil fuels, such as oil. We have a responsibility to our children and our communities to take sensible steps now to become good stewards of the air and climate we depend on to sustain us.

Earth’s climate is regulated by thNorthCarolina_tavg_Annuale greenhouse effect. The layer of greenhouse gases in the atmosphere acts like a heat-trapping blanket around the planet by capturing some of the sun’s radiation and sustaining life. Working like the glass in a greenhouse, this crucial system relies on a precise balance of atmospheric gases. Our pollution is pumping more and more of them into the atmosphere, disrupting this fragile balance. This has increased the concentration of greenhouse gases by more than one-third compared to pre-industrial levels–indeed, to the highest level in at least 3 million years. If we fail to act, we risk overheating the planet and putting our communities in danger of severe climate change.


The biggest single step we can take to fight global warming is to reduce the greenhouse gas emissions from our cars and light trucks.  The Safe Climate Campaign worked with President Obama’s administration in 2010 and 2012 to improve fuel economy and reduce tailpipe emissions to prevent climate change, cut oil dependence, and save Americans money at the gas pump. But the president can do more, by making a similar effort to cut emissions from the nation’s power plants.

We cannot ignore this challenge. By acting now, we can create a new, clean energy economy that simultaneously curbs global warming, creates jobs, and improves our security. Solving global warming will require investments in new technology and industries, which will create economic opportunities and thousands of good-paying jobs across the country. But each year of delay means more unchecked climate change, rising costs, and fewer options. A smart homeowner does not wait until it rains to fix the leaky roof. If we act responsibly, we won’t wait until it is too late to protect our fragile climate.

The Science Is Clear

The world’s leading scientists are clear: Global warming is already occurring and human activities are largely to blame. In 1988, the United Nations and the World Meteorological Association convened the Intergovernmental Panel on Climate Change (IPCC) to study the science of global warming, analyze the impacts, and recommend solutions to the problem. Thousands of scientists have contributed to the four reports the UN panel has issued. Each report presents greater consensus and conviction that humans are causing global warming, the impacts are accelerating, and we must act now to stop the most disastrous effects.

The panel’s fourth report provides some of the most comprehensive research on the subject.  According to the Intergovernmental Panel on Climate Change, we are already seeing the impact of global warming. Over the past century, the average surface temperature around the globe has increased 1.78°F (0.99°C). In addition, the years 2001 to 2016 were among the 16 hottest on record. This means that the twentieth century saw the most warming in 1,000 years in the Northern Hemisphere.


Marking the increase in atmospheric carbon from the last century

As a result of this warming, we are experiencing increasingly severe weather and rising sea levels; ice and permafrost are melting in most locations around the globe. The two most expensive storms in U.S. history–Hurricane Katrina and Super Storm Sandy–have struck since 2005. Drought plagues a wide swath of the American west. In the summer of 2012, sea ice in the Arctic covered roughly half the surface that it covered, on average, from 1979 to 2000. And over the past 20 years, the global sea level has increased at twice the rate of the previous 80 years. Over the past 100 years, it has risen roughly seven inches due in large part to the thermal expansion of warming oceans and to a lesser extent to melting glaciers that flow into the oceans. This increase in sea levels is about 10 times greater that at any point the past 3,000 years.

The speed of these changes is awesome. Temperature increases that occurred only over thousands of years in distant eras are now occurring over no more than a decade.

Fossil Fuels Are Heating Up the Planet

The primary greenhouse gas that is causing global warming is carbon dioxide (CO2), a pollutant that results when we burn such fossil fuels as coal, and natural gas. The amount of CO2 in our atmosphere has dramatically increased since the start of the industrial revolution. Current atmospheric concentrations of CO2 are 45 percent higher than pre-industrial levels and are rising rapidly. In addition to COemissions, other greenhouse gas emissions and increasing deforestation are accelerating global warming.

In the United States, nearly one-third of our greenhouse gas emissions come from transportation–primarily from the tailpipes of the cars, SUVs, and other light trucks that we drive. Tweny-nine percent comes from power plants. As the world’s largest per-capita global warming polluter, and the second largest overall, the United States has a tremendous impact on worldwide emissions. The Safe Climate Campaign is working to reduce greenhouse gas emissions from our vehicles by improving their technology. Every gallon of gasoline that we burn in our vehicles pumps 25 pounds of CO2 pollution into the atmosphere. This means that over 12 years, the average vehicle in the United States will emit more than 72 tons of global warming pollution.

Efficient cars emit less, gas guzzlers more. More carbon dioxide spews from the tailpipes of U.S. cars and light trucks than from all sources in all but five nations: China, the United States, Russia, India and Japan. In short, if the U.S. automotive fleet constituted a separate nation, it would—alone—be the sixth largest global warming polluter in the world.

Whatever we are driving, whatever appliance we are using, we are contributing some carbon to the atmosphere–and contributing to global warming. To find out how much carbon you are contributing, click here.

We Cannot Afford Delay

If we allow this warming to continue, we will face a true humanitarian and environmental crisis. A changing climate affects all aspects of our daily lives and our economy. The world’s leading climate scientists have projected that a rise of only 2° C above pre-industrial temperatures will trigger disastrous

Storm-induced flooding has wreaked havoc in Haiti, and an increase in sea levels brought on by a warming climate could strike major coastal cities around the globe.

Storm-induced flooding has wreaked havoc in Haiti, and an increase in sea levels brought on by a warming climate could strike major coastal cities around the globe.

climate change. We have already seen an increase of nearly half that scale. Rising seas will flood major cities,disrupting communities and turning millions into refugees. As the atmosphere warms, it can hold more moisture, shifting rainfall patterns and harming agriculture with more frequent and severe droughts and floods.


Global warming will also cause severe health effects from more severe heat waves. At higher temperatures, disease-carrying insects and rodents can spread such infectious diseases as malaria, dengue fever and hantavirus to communities previously unexposed to them.  

A 2006 report by Sir Nicholas Stern, the former chief economist of the World Bank, found that the costs of climate change far outweigh the costs of investing in clean energy sources to reduce emissions. Stern projected that the economic cost of global warming could be as high as 20 percent of world gross domestic product (GDP)—the total value of the goods and services produced around the world–each year. At the same time, an investment of just 1/20th of that by 2050 could stabilize emissions at safe levels and curb the worst effects of global warming. So, for every dollar we invest to solve global warming we are preventing $20 worth of damage – a return that would please any investor. Or, we can watch the costs mount: In 2010, global warming took 1.6% from global GDP, and cost the world more than $1.2 trillion, the Climate Vulnerability Monitor found.

The United States Has the Solutions to Curb Global Warming

Because this problem has been left unchecked, we cannot avoid some changes to our climate. But if we act now we can avoid the most disastrous impacts of global warming. By investing in technology that improves energy efficiency and generates energy renewably, we can curb emissions and create a vibrant new energy economy.

To read about The Biggest Single Step we can take to curb global warming, click here.