Climate Change

Climate change is a problem that is affecting people and the environment. Greater energy efficiency and new technologies hold promise for reducing greenhouse gases and solving this global challenge.

The Facts About Climate Change

  • FACT: Average global temperatures increased by about 1 degree Fahrenheit over the 20th century.
  • FACT: The United States contains only 5 percent of the world’s population, but contributes 22 percent of the world’s carbon emissions.
  • FACT: 15 percent of carbon emissions come from deforestation and land use change.
  • FACT: The Golden Toad (Bufo periglenes) is thought to be the first species to go extinct because of climate change.
  • FACT: Personal cars and trucks in the United States emit 20 percent of the United States’ carbon emissions.
  • FACT: Air conditioning and heating account for almost half of electricity use in the average American home.
  • FACT: Climate change is linked to stronger hurricanes, more drought and increased coral deaths from bleaching.
  • FACT: Climate change is linked to an increase in disease-carrying pests that lead to the increased spread of diseases such as dengue fever, malaria, lyme disease and West Nile virus.

FAQ: Climate Change

What is Climate Change?

Climate includes patterns of temperature, precipitation, humidity, wind and seasons. “Climate change” affects more than just a change in the weather, it refers to seasonal changes over a long period of time. These climate patterns play a fundamental role in shaping natural ecosystems, and the human economies and cultures that depend on them.

Because so many systems are tied to climate, a change in climate can affect many related aspects of where and how people, plants and animals live, such as food production, availability and use of water, and health risks.

For example, a change in the usual timing of rains or temperatures can affect when plants bloom and set fruit, when insects hatch or when streams are their fullest. This can affect historically synchronized pollination of crops, food for migrating birds, spawning of fish, water supplies for drinking and irrigation, forest health, and more.

Some short-term climate variation is normal, but longer-term trends now indicate a changing climate. A year or two of an extreme change in temperature or other condition doesn’t mean a climate change trend has been “erased.”

Worldwide, people are paying serious attention to climate change. In Washington state, climate change is already disrupting our environment, economy and communities. We can help slow it down, but we must take action now.


What is Global Warming?

Are climate change and global warming the same thing?

Not exactly, but they’re closely related, and some people use the terms interchangeably. Global warming causes climates to change. “Global warming” refers to rising global temperatures, while “climate change” includes other more specific kinds of changes, too. Warmer global temperatures in the atmosphere and oceans leads to climate changes affecting rainfall patterns, storms and droughts, growing seasons, humidity, and sea level.

Also, while “global warming” is planet-wide, “climate change” can refer to changes at the global, continental, regional and local levels. Even though a warming trend is global, different areas around the world will experience different specific changes in their climates, which will have unique impacts on their local plants, animals and people. A few areas might even get cooler rather than warmer.


Why is climate change a concern?

All across the world and in our state, people are taking action because climate change has serious impacts, locally and globally. For example, in 2007, scientists from the International Panel on Climate Change (IPCC) predicted that warming oceans and melting glaciers due to global warming and climate change could cause sea levels to rise 7-23 inches by the year 2100. Worldwide, densely populated coastal communities and infrastructure that supports them would be affected (such as city buildings and homes, roads, ports and wastewater treatment plants). Some would be flooded or more vulnerable to storm damage. In flat terrain, the shoreline could move many miles inland.

Other effects are also serious. In some places, floods and/or drought could become more frequent and more severe. Even seemingly less dramatic local changes in temperature, precipitation and soil moisture could severely impact many things important to human life and all life around us, including:

  • natural ecosystems
  • agriculture and food supplies
  • human health
  • forestry
  • water resources and availability
  • energy use
  • transportation

Many people are concerned that we are losing time to make a difference. Climate change and its effects may be irreversible. Life could become very difficult for some populations—plant, animal and human. Species, cultures, resources and many lives could be lost.


Is climate change really happening?

Yes. In February 2007, the Intergovernmental Panel on Climate Change (IPCC) reported to the United Nations that the Earth’s climate system is undoubtedly getting warmer.

According to the Climate Impacts Group at the University of Washington, the average annual temperature in the Pacific Northwest rose by 1.5° F in the 20th century and is expected to rise 0.5° F per decade in the first half of the 21st century.

The graph below shows the global annual temperature change since 1880. Even with variation over the years, the general trend is clearly upward. Some cooler temperatures in recent years have prompted people to ask if there is now a global cooling trend, but as the graph shows, even several years of cooling doesn’t mean a long-term warming trend is over.

Global Temperature Land-Ocean Index

The land-ocean temperature index data on the air temperatures over land with data on sea surfaces temperatures. (“Mean is the midpoint between the highest and lowest.) The black line shows the annual changes; the red line tracks 5-year periods. Source: NASA Goddards Institute for Space Studies

Although specific, individual events can’t be directly linked to global warming, the IPCC has noted many indications of climate change around the world:

  • Retreating mountain glaciers on all continents
  • Thinning ice caps in the Arctic and Antarctic
  • Rising sea level – about 6-7 inches in the 20th century
  • More frequent heavy precipitation events (rainstorms, floods or snowstorms) in many areas
  • More intense and longer droughts over wider areas, especially in the tropics and subtropics


What causes climate change and global warming?

This question has been debated a lot, because climate change can be “due to natural variability or as a result of human activity” (IPCC 2007) and because the climate system is very complex.

There is new and stronger evidence that most of the warming over the last 50 years is due to human activities. Ice cores taken from deep in ancient ice of Antarctica show that carbon dioxide levels are higher now than at any time in the past 650,000 years. More carbon dioxide in the atmosphere means warming temperatures. In its 2007 report to the United Nations, the Intergovernmental Panel on Climate Change (IPCC) concluded that it is more than 90 percent likely that the accelerated warming of the past 50-60 years is due to human contributions.

These contributions include increased levels of “heat-trapping” gases (a.k.a. “greenhouse gases”) such as carbon dioxide in the Earth’s atmosphere. One of the biggest ways people contribute to greenhouse gases is by burning fossil fuels. We use coal, oil, and natural gas to generate electricity, heat our homes, power our factories, and run our cars.

Changing land use patterns contribute, too. Trees and other plants use carbon dioxide and give off oxygen. When trees are cut down for development, agriculture, and other purposes, they’re no longer available to take carbon dioxide out of the air, and actually release carbon dioxide as they decay or burn.

As the levels of carbon dioxide and other greenhouse gases increase, more heat is “trapped” and global temperatures rise. This causes significant changes in the timing and length of the seasons as well as the amount and frequency of precipitation.


What are greenhouse gases and the greenhouse effect?

The greenhouse effect occurs as a result of greenhouse gases trapping the sun’s heat and keeping it close to the earth. Anyone who has parked a closed car in the sun for a few hours on a summer day has experienced something like the greenhouse effect. The “greenhouse effect” refers to how gases in the earth’s atmosphere naturally keep the earth warm, similar to how a greenhouse keeps plants warm, hence the name. The earth’s natural greenhouse effect keeps it about 60 degrees warmer than it would be otherwise. This enables us to live comfortably on earth. (NOAA)

graphic showing the greenhouse gas effect


Although many “greenhouse gases” occur naturally, human activities have increased their levels and added new ones. Greenhouse gases of concern include carbon dioxide, methane, nitrous oxide, and fluorinated gases. Scientists say that increased levels of these gases are contributing to climate change. Water vapor is the most abundant greenhouse gas, but human activity isn’t considered a direct cause of changes in its concentration. However, a warming atmosphere can trigger changes in water vapor levels. (NOAA) Some examples of activities that contribute to greenhouse gas levels:

  • Burning fossil fuels – oil, gasoline, gas and coal
  • Industrial processes and mining
  • Landfills, septic and sewer systems
  • Agricultural practices, including fertilizer and manure management
  • Land use practices, including deforestation


How is weather different from climate?

Weather can change from hour-to-hour, day-to-day, and season-to-season. It may rain for an hour and then become sunny and clear. Weather is what we hear about on the television news every night. It includes wind, temperature, humidity, atmospheric pressure, cloudiness, sunshine and precipitation.

Climate is the average weather for a particular region over a long time period. Climate describes the total of all weather occurring over a long period of years in a given place. This includes average weather conditions, regular weather seasons (winter, spring, summer, and fall), and special weather events (like tornadoes and floods). Climate tells us what it’s usually like in the place where you live. Historically, San Diego is known to have a mild climate, New Orleans a humid climate, Buffalo a snowy climate, and Seattle a rainy climate.

A simple way of remembering the difference is that ‘climate’ is what you expect (cool, wet winters) and ‘weather’ is what you get (a foggy morning with afternoon sunshine).


How is climate change different from ozone?

Climate change, caused by global warming, is a different problem than the ozone hole.

The ozone hole is a thinning of the stratosphere’s ozone layer, which is roughly 9 to 31 miles above the earth’s surface. The depletion of this ozone layer is due to man-made chemicals like chlorofluorocarbons (CFCs). A thinner ozone layer lets more harmful ultraviolet (UV) radiation reach the earth’s surface. This problem is now slowly improving since countries around the world agreed to stop manufacturing and using CFCs, an international agreement called the Montreal Protocol.

Global warming, on the other hand, is the increase in the earth’s average temperature due to the buildup of carbon dioxide and other greenhouse gases in the atmosphere from human activities. Global warming is causing climate change. The 1997 Kyoto Protocol was the initial effort to curb greenhouse gas production. Although many countries have agreed to the Kyoto Protocol, a remaining few, including the United States, have yet to ratify it. However, more than 400 cities in the United States, home to over 66 million people, have committed to the Kyoto goals.

Global Warming Facts & Myths

MYTH: The science of global warming is too uncertain to act on.

FACT: There is no debate among scientists about the basic facts of global warming.

The most respected scientific bodies have stated unequivocally that global warming is occurring, and people are causing it by burning fossil fuels (like coal, oil and natural gas) and cutting down forests. The U.S. National Academy of Sciences, which in 2005 the White House called “the gold standard of objective scientific assessment,” issued a joint statement with 10 other National Academies of Science saying “the scientific understanding of climate change is now sufficiently clear to justify nations taking prompt action. It is vital that all nations identify cost-effective steps that they can take now, to contribute to substantial and long-term reduction in net global greenhouse gas emissions.” (Joint Statement of Science Academies: Global Response to Climate Change [PDF], 2005)

The only debate in the science community about global warming is about how much and how fast warming will continue as a result of heat-trapping emissions. Scientists have given a clear warning about global warming, and we have more than enough facts — about causes and fixes — to implement solutions right now.


MYTH: Even if global warming is a problem, addressing it will hurt American industry and workers.

FACT: A well designed trading program will harness American ingenuity to decrease heat-trapping pollution cost-effectively, jumpstarting a new carbon economy.

Claims that fighting global warming will cripple the economy and cost hundreds of thousands of jobs are unfounded. In fact, companies that are already reducing their heat-trapping emissions have discovered that cutting pollution can save money. The cost of a comprehensive national greenhouse gas reduction program will depend on the precise emissions targets, the timing for the reductions and the means of implementation. An independent MIT study found that a modest cap-and-trade system would cost less than $20 per household annually and have no negative impact on employment.

Experience has shown that properly designed emissions trading programs can reduce compliance costs significantly compared with other regulatory approaches. For example, the U.S. acid rain program reduced sulfur dioxide emissions by more than 30 percent from 1990 levels and cost industry a fraction of what the government originally estimated, according to EPA. Furthermore, a mandatory cap on emissions could spur technological innovation that could create jobs and wealth. Letting global warming continue until we are forced to address it on an emergency basis could disrupt and severely damage our economy. It is far wiser and more cost-effective to act now.


MYTH: Water vapor is the most important, abundant greenhouse gas. So if we’re going to control a greenhouse gas, why don’t we control it instead of carbon dioxide (CO2)?

FACT: Although water vapor traps more heat than CO2, because of the relationships among CO2, water vapor and climate, to fight global warming nations must focus on controlling CO2.

Atmospheric levels of CO2 are determined by how much coal, natural gas and oil we burn and how many trees we cut down, as well as by natural processes like plant growth. Atmospheric levels of water vapor, on the other hand, cannot be directly controlled by people; rather, they are determined by temperatures. The warmer the atmosphere, the more water vapor it can hold. As a result, water vapor is part of an amplifying effect. Greenhouse gases like CO2 warm the air, which in turn adds to the stock of water vapor, which in turn traps more heat and accelerates warming. Scientists know this because of satellite measurements documenting a rise in water vapor concentrations as the globe has warmed. The best way to lower temperature and thus reduce water vapor levels is to reduce CO2 emissions.


MYTH: Global warming and extra CO2 will actually be beneficial — they reduce cold-related deaths and stimulate crop growth.

FACT: Any beneficial effects will be far outweighed by damage and disruption.

Even a warming in just the middle range of scientific projections would have devastating impacts on many sectors of the economy. Rising seas would inundate coastal communities, contaminate water supplies with salt and increase the risk of flooding by storm surge, affecting tens of millions of people globally. Moreover, extreme weather events, including heat waves, droughts and floods, are predicted to increase in frequency and intensity, causing loss of lives and property and throwing agriculture into turmoil.

Even though higher levels of CO2 can act as a plant fertilizer under some conditions, scientists now think that the “CO2 fertilization” effect on crops has been overstated; in natural ecosystems, the fertilization effect can diminish after a few years as plants acclimate. Furthermore, increased CO2 may benefit undesirable, weedy species more than desirable species.

Higher levels of CO2 have already caused ocean acidification, and scientists are warning of potentially devastating effects on marine life and fisheries. Moreover, higher levels of regional ozone (smog), a result of warmer temperatures, could worsen respiratory illnesses. Less developed countries and natural ecosystems may not have the capacity to adapt.

The notion that there will be regional “winners” and “losers” in global warming is based on a world-view from the 1950’s. We live in a global community. Never mind the moral implications — when an environmental catastrophe creates millions of refugees half-way around the world, Americans are affected.


MYTH: Global warming is just part of a natural cycle. The Arctic has warmed up in the past.

FACT: The global warming we are experiencing is not natural. People are causing it.

People are causing global warming by burning fossil fuels (like oil, coal and natural gas) and cutting down forests. Scientists have shown that these activities are pumping far more CO2 into the atmosphere than was ever released in hundreds of thousands of years. This buildup of CO2 is the biggest cause of global warming. Since 1895, scientists have known that CO2 and other greenhouse gases trap heat and warm the earth. As the warming has intensified over the past three decades, scientific scrutiny has increased along with it. Scientists have considered and ruled out other, natural explanations such as sunlight, volcanic eruptions and cosmic rays. (IPCC 2001)

Though natural amounts of CO2 have varied from 180 to 300 parts per million (ppm), today’s CO2 levels are around 380 ppm. That’s 25% more than the highest natural levels over the past 650,000 years. Increased CO2 levels have contributed to periods of higher average temperatures throughout that long record. (Boden, Carbon Dioxide Information Analysis Center)

As for previous Arctic warming, it is true that there were stretches of warm periods over the Arctic earlier in the 20th century. The limited records available for that time period indicate that the warmth did not affect as many areas or persist from year to year as much as the current warmth. But that episode, however warm it was, is not relevant to the issue at hand. Why? For one, a brief regional trend does not discount a longer global phenomenon.

We know that the planet has been warming over the past several decades and Arctic ice has been melting persistently. And unlike the earlier periods of Arctic warmth, there is no expectation that the current upward trend in Arctic temperatures will reverse; the rising concentrations of greenhouse gases will prevent that from happening.


MYTH: We can adapt to climate change — civilization has survived previous shifts in global climate patterns.

FACT: Although humans as a whole have survived the vagaries of drought, stretches of warmth and cold and more, entire societies have collapsed from dramatic climatic shifts.

The current warming of our climate will bring major hardships and economic dislocations — untold human suffering, especially for our children and grandchildren. We are already seeing significant costs from today’s global warming which is caused by greenhouse gas pollution. Climate has changed in the past and human societies have survived, but today six billion people depend on interconnected ecosystems and complex technological infrastructure.

What’s more, unless we limit the amount of heat-trapping gases we are putting into the atmosphere, we will face a warming trend unseen since human civilization began 10,000 years ago. (IPCC 2001)

The consequences of continued warming at current rates are likely to be dire. Many densely populated areas, such as low-lying coastal regions, are highly vulnerable to climate shifts. A middle-of-the-range projection is that the homes of 13 to 88 million people around the world would be flooded by the sea each year in the 2080s. Poorer countries and small island nations will have the hardest time adapting. (McLean et al. 2001)

In what appears to be the first forced move resulting from climate change, 100 residents of Tegua island in the Pacific Ocean were evacuated by the government because rising sea levels were flooding their island. Some 2,000 other islanders plan a similar move to escape rising waters. In the United States, the village of Shishmaref in Alaska, which has been inhabited for 400 years, is collapsing from melting permafrost. Relocation plans are in the works.

Scarcity of water and food could lead to major conflicts with broad ripple effects throughout the globe. Even if people find a way to adapt, the wildlife and plants on which we depend may be unable to adapt to rapid climate change. While the world itself will not end, the world as we know it may disappear.


MYTH: Recent cold winters don’t feel like global warming to me.

FACT: While different pockets of the country have experienced some cold winters here and there, the overall trend is warmer winters.

Measurements show that over the last century the Earth’s climate has warmed overall, in all seasons, and in most regions. Climate skeptics mislead the public when they claim that the winter of 2003–2004 was the coldest ever in the northeastern United States. That winter was only the 33rd coldest in the region since records began in 1896. Furthermore, a single year of cold weather in one region of the globe is not an indication of a trend in the global climate, which refers to a long-term average over the entire planet.


MYTH: Global warming can’t be happening because some glaciers and ice sheets are growing, not shrinking.

FACT: In most parts of the world, the retreat of glaciers has been dramatic. The best available scientific data indicate that Greenland’s massive ice sheet is shrinking.

Between 1961 and 1997, the world’s glaciers lost 890 cubic miles of ice. The consensus among scientists is that rising air temperatures are the most important factor behind the retreat of glaciers on a global scale over long time periods. Some glaciers in western Norway, Iceland and New Zealand have been expanding during the past few decades. That expansion is a result of regional increases in storm frequency and snowfall rather than colder temperatures — not at all incompatible with a global warming trend.

In Greenland, a NASA satellite that can measure the ice mass over the whole continent has found that although there is variation from month to month, over the longer term, the ice is disappearing. In fact, there are worrisome signs that melting is accelerating: glaciers are moving into the ocean twice as fast as a decade ago, and, over time, more and more glaciers have started to accelerate. What is most alarming is the prediction, based on model calculations and historical evidence, that an approximately 5.4 degree Fahrenheit increase in local Greenland temperatures will lead to irreversible meltdown and a sea-level rise of over 20 feet. Since the Arctic is warming 2-3 times faster than the global average, this tipping point is not far away.

The only study that has shown increasing ice mass in Greenland only looked at the interior of the ice sheet, not at the edges where melting occurs. This is actually in line with climate model predictions that global warming would lead to a short-term accumulation of ice in the cold interior due to heavier snowfall. (Similarly, scientists have predicted that Antarctica overall will gain ice in the near future due to heavier snowfall.) The scientists who published the study were careful to point out that their results should not be used to conclude that Greenland’s ice mass as a whole is growing. In addition, their data suggested that the accumulation of snow in the middle of the continent is likely to decrease over time as global warming continues.


MYTH: Accurate weather predictions a few days in advance are hard to come by. Why on earth should we have confidence in climate projections decades from now?

FACT: Climate prediction is fundamentally different from weather prediction, just as climate is different from weather.

It is often more difficult to make an accurate weather forecast than a climate prediction. The accuracy of weather forecasting is critically dependent upon being able to exactly and comprehensively characterize the present state of the global atmosphere. Climate prediction relies on other, longer ranging factors. For instance, we might not know if it will be below freezing on a specific December day in New England, but we know from our understanding of the region’s climate that the temperatures during the month will generally be low. Similarly, climate tells us that Seattle and London tend to be rainy, Florida and southern California are usually warm, and the Southwest is often dry and hot.

Today’s climate models can now reproduce the observed global average climates over the past century and beyond. Such findings have reinforced scientist’s confidence in the capacity of models to produce reliable projections of future climate. Current climate assessments typically consider the results from a range of models and scenarios for future heat-trapping emissions in order to identify the most likely range for future climatic change.


MYTH: As the ozone hole shrinks, global warming will no longer present an issue.

FACT: Global warming and the ozone hole are two different problems.

The ozone hole is a thinning of the stratosphere’s ozone layer, which is roughly 9 to 31 miles above the earth’s surface. The depletion of the ozone is due to man-made chemicals like chlorofluorocarbons (CFCs). A thinner ozone layer lets more harmful ultraviolet (UV) radiation to reach the earth’s surface.

Global warming, on the other hand, is the increase in the earth’s average temperature due to the buildup of CO2 and other greenhouse gases in the atmosphere from human activities.