Climate Change photo identifier

Climate Change

Frequently asked questions about climate change:

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 news or weather report. It includes wind, temperature, humidity, atmospheric pressure, cloudiness, sunshine and precipitation (rain or snow).

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).

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, arctic ice (and the northern jet stream that drives our weather), frequency and intensity of storms and droughts, growing seasons, humidity, melting polar and glacial ice, 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 local plants, animals and people. A few areas might even get cooler rather than warmer, and extreme weather events can include snowstorms as well as heat waves.

Why is climate change a concern?

Rising levels of carbon dioxide and other heat-trapping gases have warmed the earth and are already causing wide-ranging impacts, from rising sea levels, to melting snow and ice, to more drought and extreme rainfall. Scientists project that these trends will continue and in some cases accelerate, posing significant risks to human health, our forests, agriculture, freshwater supplies, coastlines, and other natural resources that are vital to Washington State’s economy, environment, and our way of life.

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.

Extreme weather
Extreme weather has become more common in the United States since 1980, and part of that shift is due to climate change. In 2011 the U.S. experienced 14 extreme weather-related events that caused loss of human life and cost the U.S. economy more than $55 billion. The year 2012 broke the most U.S. heat records of any year to date, and tied with 1998 for the most extreme weather events. July 2012 was the hottest month ever in the U.S. since the government began recording temperatures in 1895, and two-thirds of the U.S. was affected by extreme drought in the summer of 2012. Record wildfires raged across the U.S., including Washington state where 245 miles of forests burned.

Source: NASA Goddard

Temperatures, rainfall, droughts, high-intensity hurricanes and severe flooding events all are increasing and projected to continue as the world's climate warms, according to the National Climate Assessment for 2012.

Floods expected to happen once every 100 or 500 years are beginning to occur more often. In Washington state, between 1990 and 2009, the Chehalis River experienced four “‘100-year” floods and one “500-year” flood event, costing millions of dollars in cleanup and repair.

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:

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

Many people are concerned that we are losing time to make a difference. Climate change and its effects appear to be accelerating faster than scientists had predicted. For more about how climate change could affect our state, see:


Is climate change really happening?

Every National Academy of Science of every major country in the world that has studied climate change has confirmed that it is real and humans are causing it. In May 2009, the National Academies of Science said: “the need for urgent action to address climate change is now indisputable.”

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. (This graph doesn’t include higher temperatures through 2011 and 2012.)

Global Temperature Land-Ocean Index

The land-ocean temperature index combines data on air temperatures over land with data on sea surface 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 Goddard institute for Space Studies. (January 11, 2008)

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
  • Record thinning ice caps in the Arctic and Antarctic
  • Rising sea level – about 6-7 inches in the 20th century
  • More frequent heavy precipitation events (snowstorms, rainstorms, and floods) 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 was historically debated, because climate change can be due to natural variability or as a result of human activity and because the climate system is very complex.

There is new and stronger evidence that most of the warming over the past 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 (CO2) in the Earth’s atmosphere. Measurements of carbon dioxide levels in air trapped in the polar ice sheets, together with atmospheric observations made since the 1950s, show that the concentration of CO2 has risen by about one third since the early 19th century. The level of CO2 in the atmosphere rose from around 280 parts per million (ppm) in preindustrial times to 392 ppm in 2012 and is still rising.

As the levels of carbon dioxide and other greenhouse gases, 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 in rain or snow.

Why would we care?

Here are a few simple examples of climate changes due to global warming:

  • As temperatures rise, more moisture evaporates from the oceans (like water evaporates faster as heat is added to a kettle). The air above the oceans now holds 4 percent more water vapor than 30 years ago. Bigger storms are one result.
  • Warmer air over land evaporates more water from soil and plants and can create or extend drought.
  • Global warming has increased the loss of summer sea ice in the Arctic, which has altered atmospheric conditions that influence harsher winter weather in the U.S. and Europe.
  • Warmer air also warms glacier ice in Greenland and other lands and that melting water adds to sea level rise, as does the expansion of warmer ocean water.
  • Warmer air melts permafrost (previously permanently frozen ground in northern latitudes) and melted permafrost releases methane from ancient decayed vegetation in thawing soils. Methane is another potent greenhouse gas which further adds to global warming.

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 absorb 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.


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 has already added 4 percent more water vapor over the oceans in the last 30 years. (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

Is Arctic Ice important to us or just to polar bears?

Arctic ecosystems are critical habitat for polar bears and loss of arctic sea ice is threatening polar bear survival. They can swim strong and far between ice flows where they hunt seals, but even polar bears cannot swim forever and many are drowning in growing expanses of open water. But increasingly “polar bears are us,” because loss of arctic ice also has a big impact on our own weather.

Global warming has melted summer sea ice in the Arctic, and since 2007 arctic ice losses have increased dramatically with successive record lows through September 2012 (last reading to date). "While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur. The six lowest September ice extents have all been in the past six years. We are now in uncharted territory," Mark Serreze, director of the National Snow and Ice Data Center, said in a statement announcing the 2012 record low of 1.32 million square miles — nearly half the average arctic ice extent from 1979 to 2010. The extent has been tracked by satellite since 1979.

The extent of arctic ice affects the jet stream and atmospheric conditions that influence harsh winter weather in the U.S. and Europe. As warmer air over the Arctic melts the Arctic ice cap, it leaves a dark ocean to absorb the sun’s rays and put more warmth into the Arctic air, which weakens the tight swirling vortex of the jet stream. The jet stream is what drives northern weather patterns, so as a weaker jet stream dips further south it changes delivery of our storm tracks. These changes lead to invasions of Arctic air into the middle latitudes, increasing the likelihood of severe winter outbreaks, which occurred in the eastern U.S. and northern Europe in 2010 and 2011 and in eastern Europe in January 2012, and across the U.S. in winter of 2012-2013.


Why are melting glaciers a concern?

Sea level rise is one concern. As global warming continues to accelerate the melting of glacier ice in Greenland and other lands, that melting water adds to sea level rise, as does the expansion of warmer ocean water. Since many of the world’s most populous cities are located on coasts, sea level rise is a growing threat. Washington has more than 3,000 miles of marine shoreline and a growing coastal population. Around 70 percent of Washington’s population lives, works, and plays in counties that border the coast. Coastal communities are particularly vulnerable to the effects of climate change, which puts much of the state’s population at risk – homes, infrastructure, livelihoods, and even lives.

Water availability is another big concern. In Washington State, warmer temperatures mean more precipitation will fall as rain, not snow, and more snow will melt earlier in the spring. In Washington’s Cascades average snowpack declined about 25 percent between 1950 and 2006, with the largest decreases occurring in lower elevations. Mountain glaciers in the North Cascades have lost 18 to 32 percent of their total volume since 1983 and 53 North Cascades glaciers have disappeared since the 1950s.

Spring snowpack across Washington state is projected to decrease 28 percent by the 2020s and 40 percent by the 2040s, relative to the 1916-2006 average, and snowmelt is expected to occur earlier in the spring. Already we see stream flows are peaking earlier in the year in watersheds throughout the state, including the Columbia Basin.

Much of Washington’s water supply is stored in snow pack and glaciers that melt into rivers. As this stored snow recedes to higher elevations, less will be available to feed rivers. Too much water runoff (melted snow) through early spring when it's not needed will result in less runoff in summer when it is needed. Less snow means that glaciers are not replenished. Downstream effects include changes in • timing of peak fresh water flows, • hydropower output, • fish migration, and • water availability in the dry summer season (for crops, fish, and people.)


Are humans contributing greenhouse gases that cause global warming?

In 2007, the United Nations Intergovernmental Panel on Climate Change (IPCC) said global warming is an unequivocal fact and that "most of the observed increases in globally-averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (human-caused) greenhouse gas concentrations." The IPCC term “very likely” is equivalent to 90-94 percent likelihood.

The (IPCC) is one of the largest bodies of international scientists ever assembled to study a scientific issue, involving more than 2,500 scientists from more than 130 countries. Its findings have been publicly endorsed by the national academies of science of all G-8 nations, as well as those of China, India and Brazil.

The following observed lines of scientific evidence all reflect data that shows significant human-caused global warming: ocean heat content and sea surface temperatures, ocean air temperature, sea ice extent, northern hemisphere snow cover, inland lake temperatures, sea level rise, glacier volume, troposphere and stratosphere air temperatures, specific humidity, and temperatures over land. (NOAA)


Is it too late to do something about climate change?

No, it’s not too late. In fact we must act to slow the progression of climate change, even if we can’t stop it completely due to greenhouse gases already in the atmosphere.

Our state and societies around the globe need to reduce greenhouse gas emissions to avoid worsening climate impacts and reduce the risk of creating changes beyond our ability to respond and adapt. Washington state is addressing this challenge and has adopted policies to reduce energy use, limit greenhouse gas emissions, and build a clean energy economy. (See Ecology website) Some changes in climate—and impacts on our state—are unavoidable, even if we reduce greenhouse gas emissions today.

By taking action now to respond and adapt to changing climate conditions, Washington can significantly limit the damage and reduce the long-term costs of the climate related impacts that are expected to grow in number and intensity in the decades to come.


Encouraging trends and examples

Fossil fuels responsible for greenhouse gases are beginning to be replaced by greener energy alternatives at a rate growing much faster than projected just a decade ago. For instance, in 2010, for the first time ever, global investment in new renewable energy projects exceeded investment in new fossil fuel projects.

In 2010, $187 billion was invested in new renewable energy projects — almost 20 percent more than new fossil fuel projects. According to the United Nations Environment Program, global investment in renewable energy and fuels was $257 billion in 2011, a 17 percent increase from the previous year. In 2011, renewable sources supplied nearly 17 percent of global energy.


Wind energy growth

The U.S. Department of Energy projected in 1999 that the U.S. would have 10 Gigawatts of installed wind capacity by 2010, but that goal was met by 2006 and by the first half of 2012 nearly 50 Gigawatts of wind energy was installed, which is enough to power more than 12 million homes for a year. Nearly a third of new electric capacity in the U.S. in 2011 came from wind.


Solar energy growth

Another fast-growing renewable energy source is solar power. In Morocco, they are building a super grid that will deliver solar energy across Sub-Saharan Africa and even to Europe. Spain has a solar thermal ‘power tower’ to store solar energy after sunset, and solar thermal is now installed in California, as well as concentrating solar power (CSP) technology in California’s Mohave Desert. Great Britain has solar farms outside of Cornwall, England at the site of a reclaimed tin mine. Germany increased their energy from solar power by 50 per cent in 2012, and all renewable energies combined (wind, solar and biomass) accounted for about 26 percent of German electricity production over the first nine months of that year. It is worth noting that both England and Germany are in cloudy climates in latitudes close to our own in Washington state, and if they can do it, so can we!

There were projections in 2002 that the global solar energy market would grow about 1 Gigawatt per year by 2010. But in 2012 the market was growing at about 17 times that pace. A top solar industry analyst predicted in 2002 that the global solar industry would add approximately 1 Gigawatt of new capacity every year by 2010. However, in 2010, the amount of new solar photovoltaic capacity added in that single year was actually 17 Gigawatts (17 times the projection).

The production of solar photovoltaic cells in China and Taiwan (60% of world production) grew more than 1000% between 2007 and 2010. In the U.S., production increased more than 300% over the same period. The installed solar photovoltaic energy in the U.S. more than doubled between 2009 and 2010, from 435 megawatts to 878 megawatts.


Reducing CO2 emissions with carbon tax or cap & trade?

Both cap-and-trade systems and carbon taxes give polluters a financial incentive to reduce their greenhouse gas emissions. And both are already in place with varying degrees of success. Carbon taxes are already used in India, Japan, Australia, Denmark, Switzerland, Costa Rica and British Columbia, Canada.

Cap and trade is in place in some states. The Regional Greenhouse Gas Initiative (RGGI) was the first market-based regulatory program in the United States to reduce greenhouse gas emissions. RGGI is a cooperative effort among 9 northeast states to cap and reduce CO2 emissions from the power sector. This is known as a “cap and trade” program and early in 2013, they lowered the cap.

The California legislature approved cap-and-trade in 2006 and the state held its first auction of emissions permits in 2012 after developing the rules. Although some find the rules controversial, it is a start. Even in economic hard times, this law was reinforced by the electorate in 2010 when California voters overwhelmingly rejected a proposition that would have suspended the law until the state's unemployment rate dropped under 5.5 percent for a full year.

Early in 2013, Governor Inslee suggested a study of effective carbon reduction programs to help Washington State craft a plan to further reduce greenhouse gas reductions, slow climate change, and grow the state’s economy.


What can I do about climate change?

There are many ways you can be aware and help slow climate change! From simple to more challenging actions you can take at home, when traveling, at work or school, and in your community as a climate-concerned citizen. See What YOU can do and make a commitment to do even more than you have already done.

Many people are innovating, contributing and taking action to slow climate change. Green energy is rapidly outpacing fossil fuels as the energy source of the 21st Century, and in 2010 for the first time global investments in green energy exceeded those in fossil fuels. In 2011, renewable sources supplied nearly 17 percent of global energy (pfd).


Why do some doubt that climate is changing?

The consensus among climate scientists is that global warming is real, primarily caused by human activity, and a serious threat to our future. Yet others, including media extremists, partisan think tanks, and special interest groups funded by fossil fuel and related industries, continue to raise doubts.

See what others are saying about skeptics, who are the climate deniers and who funds them.

The overwhelming majority of scientists who study climate change agree that human activity is responsible for changing the climate. The United Nations Intergovernmental Panel on Climate Change (IPCC) is one of the largest bodies of international scientists ever assembled to study a scientific issue, involving more than 2,500 scientists from more than 130 countries. The IPCC has concluded that most of the warming observed during the past 50 years is attributable to human activities. Its findings have been publicly endorsed by the national academies of science (pdf) of all G-8 nations, as well as those of China, India and Brazil.


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.

How is climate change related to ocean acidification?

Climate change is related to but distinct from and ocean acidification. Climate change and ocean acidification share a common cause — increasing carbon dioxide in the atmosphere. Climate change encompasses the effects associated with changes in the Earth’s temperature, which cause global warming and changes in weather patterns. Ocean acidification refers to the lowering of ocean pH resulting from its absorption of CO2 released from the atmosphere. Ocean acidification does not include the warming of the ocean. (C.L. Sabine)

See more about ocean acidification in Washington State.

How can we prepare for climate changes we cannot prevent?

Many greenhouse gases already in the earth’s atmosphere today will remain for decades to come, continuing the progression of global warming. We can stop adding ever more greenhouse gases if we change our energy use, among other practices. Rapid improvements already underway around the world can help slow the progression of climate change, but we must fast-track action in our own state, nationally and globally.

By taking action now to respond and adapt to changing climate conditions, Washington can significantly limit the damage and reduce the long-term costs of the climate related impacts that are expected to grow in number and intensity in the decades to come. If no action is taken, potential costs to Washington from climate change impacts are projected to reach nearly $10 billion per year by 2020 from increased health costs, storm damage, coastal destruction, rising energy costs, increased wildfires, drought, and other impacts.

Preparing for a Changing Climate: Washington State’s Integrated Climate Change Response Strategy, lays out a framework to protect our communities, natural resources, and economy from the impacts of climate change and build our capacity to adapt to expected climate changes. It describes how existing and new state policies and programs can better prepare Washington to respond to the impacts of climate change.

It calls on state agencies to make climate adaptation a standard part of agency planning and to make scientific information about climate change impacts readily accessible to decision makers in the public and private sectors. It also recommends that state agencies strengthen existing efforts and build partnerships to help local and tribal governments, private and public organizations, and individuals reduce their vulnerability to climate change impacts.

Ecology prepared this response strategy in collaboration with the state departments of Agriculture, Commerce, Fish and Wildlife, Health, Natural Resources, and Transportation. A broad range of stakeholders with policy, management, and scientific expertise participated in four advisory groups and developed a set of recommendations for near- and long-term actions to prepare Washington for a changing climate.


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