Weather and Climate: What's the Difference?
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The effects of global warming are frequently projected decades into the future, but two recent reports -- one from theU.S. Global Change Research Program
and the otherfrom the U.N.
-- put into sharp focus visible consequences of our warming planet. An increase in temperature, extreme weather, loss of ice and rising sea level are just a few of changes we can measure right now. Let's take a look at some of the most concerning trends.BLOG: War Of The Words: Climate Change Or Global Warming?
Glaciers are shrinking worldwide and permafrost is thawing in high-latitude and high-elevation areas, reports this year's Fifth Assessment Report from the Intergovernmental Panel on Climate Change.BLOG: Dire Outlook For Climate Impacts, New Report Says
Only a few extinctions are attributed to climate change, reports the IPCC, but climate change that occurred much more slowly, over millions of years, caused major ecosystem shifts and species extinctions. Land and sea animals are changing their geographic ranges and migratory patterns due to climate change.NEWS: Climate Change: Why Haven't We Done More?
Sea level around the world has increased by about 8 inches since 1880, reports the 2014 National Climate Assessment, which projects a 1 to 4 foot rise by the end of the century.PHOTOS: Craziest Environmental Ideas (That Could Work)
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Excess CO2 is dissolving in the ocean and decreasing the pH of seawater. The ocean is about 30 percent more acidic than it was in pre-industrial times. More acidity in the oceans makes it harder for animals to form calcium carbonate shells and skeletons and erodes coral reefs.11 Health Threats from Climate Change
The probability of a Sandy-like storm deluging New York, New Jersey and other parts of the East Coast has nearly doubled compared to 1950, according to the American Meteorological Society. Even weaker storms will be more damaging now than they were 10 years ago because of rising sea levels. Superstorm Sandy cost the nation $65 billion, according to the 2014 National Climate Assessment, and 2012's Hurricane Isaac cost $2.3 billion.
The global sea level rises along with the temperature for two major reasons. For one, heat causes water to expand, which causes the existing water to take up more space and encroach on the coast. At the same time, ice at the poles and in glaciers melts and increases the amount of water in the oceans.PHOTOS: Melting Glaciers
Across the United States, heavy downpours are on the rise, especially in the Northeast and Midwest. Increases in extreme precipitation are expected for all U.S. regions, reports the 2014 National Climate Assessment.NEWS: Shrinking Greenland Glacier Smashes Speed Record
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The most recent IPCC report states with "very high confidence" that current climate-related extremes like heat waves, droughts, floods, cyclones and wildfires are showing that countries around the world, at all development levels, are significantly unprepared. The American Meteorological Society estimates that approximately 35 percent of the extreme heat in the eastern United States between March and May 2012 resulted from human activities' effects on climate. The AMS warned that deadly heat waves will become four times more likely in the north-central and northeastern United States as the planet continues to warm.NASA: Global Warming Goes On
Here’s a phrase heard often in the winter, when temperatures are, naturally, colder than at any other time of year: “Global warming? Yeah right, more like global cooling.” But that reveals a basic misunderstanding of what “weather” and “climate” are.
The difference between weather and climate comes down to time. Weather refers to the state of the atmosphere at a particular time or over a few weeks and months. Temperature, humidity, precipitation, cloud cover, windiness and other factors make up a particular time period’s weather.
Climate refers to the average weather for a place over a period of many years. Climate scientists often use 30-year intervals to define a region’s climate, according to the National Snow and Ice Data Center.
For example, sunny, cloudless and 62 degrees Fahrenheit describes the weather this morning here in central Missouri, in other words, a perfect spring day. However, yesterday’s weather was cloudy with scattered showers, while a few days before it was 90 degrees F. These were changes in the weather, not the climate.
The weather in Missouri varies greatly from day to day and even hour to hour. However, on average, the surface temperatures here have been increasing during the past several decades. Other places, especially the polar regions, experienced more dramatic average temperature increases during the same time period.
The gradual alteration of average weather patterns defines climate change. Earth’s climate changes naturally, which is why we no longer sit under a mile of ice in Missouri, nor do we have lush jungles anymore.
However, certain human activities can influence the climate. Burning fossil fuels releases carbon dioxide. Domesticated cattle release methane when they pass gas, as do the termites that devour wood scraps left by loggers. Methane and carbon dioxide can change the climate. Those gases allow the sun’s light to pass through the atmosphere. Yet after that light strikes Earth’s surface and transforms into heat, the gases trap that warmth, just like the glass or plastic panes of a greenhouse. Chemists define that process as the greenhouse effect.
The term “anthropogenic” describes human-caused climate change. Athrōpos means human in ancient Greek. The suffix -genic means produced or generated by something. Since no natural explanation exists for the current rapid increases in average temperature, geophysicists and climate scientists consider the past several decades of climate change to be anthropogenic.
Image: The map depicts land surface temperatures of March 8-15, 2012 compared to the average of the same eight day period from 2000-2011. Areas with warmer-than-average temperatures are shown in red; near-normal temperatures are white; and areas that were cooler than the 2000-2011 base period are blue. Credit: NASA Earth Observatory image by Jesse Allen, Wikimedia Commons