Pouring Cold Water On Skeptics' Claims Earlier this month, the Intergovernmental Panel on Climate Change (IPCC) released a report that confirmed and refined what scientists already knew: The recent global warming trend is real, it is caused primarily by human activities, and we can expect further dangerous warming of a few degrees if we don't reduce our emissions of greenhouse gases. Despite the very high level of confidence that the IPCC placed on this assertion, climate skeptics refuse to allow themselves to be convinced by the facts. Global warming deniers -- desperate for any information that might contravene the science -- have latched onto this month's colder-than-normal temperatures that have gripped much of the United States, particularly the Northeast and mid-Atlantic regions. In a recent headline, the Drudge Report joked, "Hearing on 'warming of planet' canceled because of ice storm." Many on the right have cited the joke as actual proof that climate change isn’t occurring. The right-wing publication Newsmax.com referenced the headline to claim global warming is part of the "current media fed hysteria." In fact, the temperature patterns we are currently experiencing are exactly what increasing greenhouse gas emissions predicts: climate destabilization. Still, many wonder why is it so cold if there's global warming? Today's Progress Report tells you what you need to know to counter the skeptics.
DISTINCTION BETWEEN WEATHER AND CLIMATE: To understand why the current cold snap across the United States is occurring during a global warming trend, one must first understand the distinction between climate and weather. Climate is the "composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years." In other words, climate refers to recorded history. Weather, on the hand, is current events; it refers to the "state of the atmosphere at a given time and place." Weather is a snapshot of the climate at any one instant. Although the two are related, their relationship is indirect. "The chaotic nature of weather means that no conclusion about climate can ever be drawn from a single data point, hot or cold. The temperature of one place at one time...says nothing about climate, much less climate change, much less global climate change."
WHY ALL THE SNOW?: Scientists have said "snowfall is often predicted to increase in many regions in response to anthropogenic [human-induced] climate change, since warmer air, all other things being equal, holds more moisture, and therefore, the potential for greater amounts of precipitation whatever form that precipitation takes." Based on computer models, a recent study by the National Center for Atmospheric Research (NCAR) found, "As Earth gets warmer, large regions will experience heavier rain and snowfall as weather becomes generally more intense." The reason for the increase in storm intensity is that as the planet warms, "the temperatures of the atmosphere and of the ocean surface go up as well, leading to increased evaporation and an increased capacity for the air to hold moisture. As this soggy air moves from ocean to land, the storms that form are heavier with rain or snow." The NCAR climate models have predicted that heavier rains and/or snow would most likely affect regions where large masses of air converge, including northwestern and northeastern North America. Take for instance the record snowfall that has hit upstate New York. This event would be predicted by the climate models because the "lake effect" snowfalls are greatly influenced by the warm waters of Lake Ontario. As cold Arctic air moves over the warm waters, the water evaporates and cools, it condenses to form clouds, and the clouds ultimately produce snowfall. The warmer the lake waters, the more snow that will be produced. True to form, the waters on Lake Ontario this year were warmer than usual. "This winter, there's no way the lake will freeze." Therefore, a cold snap heightens the chance of heavy snow.
A CLEAR WARMING TREND: The long-term trends present clear evidence that climate change is "real and serious." The IPCC report noted that the "the warmth of the last half century is unusual in at least the previous 1300 years." Of the 12 hottest years on record, 11 have occurred since 1995. The 2006 average annual temperature for the contiguous United States was the warmest on record and nearly identical to the record set in 1998, according to scientists at the National Oceanic & Atmospheric Administration's National Climatic Data Center. In 2006, five states had their warmest December on record (Minnesota, New York, Connecticut, Vermont, New Hampshire) and no state was colder than average. The Japan Meteorological Agency reported that January 2007 was the world's hottest January on record, with temperatures across the planet registering 0.45 degrees Celsius (0.8 degrees Fahrenheit) above average. Residents of the Washington, D.C. metropolitan area have this week been hit by a "gusty wintry wallop" and are experiencing below-average temperatures for this month. Yet, the deviation below the average temperature for February is still less than the above-average deviation that D.C. residents experienced during the month of January. While the climate change trend is clear, the weather patterns at different moments in time will be hard to predict.
DISTINCTION BETWEEN WEATHER AND CLIMATE: To understand why the current cold snap across the United States is occurring during a global warming trend, one must first understand the distinction between climate and weather. Climate is the "composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years." In other words, climate refers to recorded history. Weather, on the hand, is current events; it refers to the "state of the atmosphere at a given time and place." Weather is a snapshot of the climate at any one instant. Although the two are related, their relationship is indirect. "The chaotic nature of weather means that no conclusion about climate can ever be drawn from a single data point, hot or cold. The temperature of one place at one time...says nothing about climate, much less climate change, much less global climate change."
WHY ALL THE SNOW?: Scientists have said "snowfall is often predicted to increase in many regions in response to anthropogenic [human-induced] climate change, since warmer air, all other things being equal, holds more moisture, and therefore, the potential for greater amounts of precipitation whatever form that precipitation takes." Based on computer models, a recent study by the National Center for Atmospheric Research (NCAR) found, "As Earth gets warmer, large regions will experience heavier rain and snowfall as weather becomes generally more intense." The reason for the increase in storm intensity is that as the planet warms, "the temperatures of the atmosphere and of the ocean surface go up as well, leading to increased evaporation and an increased capacity for the air to hold moisture. As this soggy air moves from ocean to land, the storms that form are heavier with rain or snow." The NCAR climate models have predicted that heavier rains and/or snow would most likely affect regions where large masses of air converge, including northwestern and northeastern North America. Take for instance the record snowfall that has hit upstate New York. This event would be predicted by the climate models because the "lake effect" snowfalls are greatly influenced by the warm waters of Lake Ontario. As cold Arctic air moves over the warm waters, the water evaporates and cools, it condenses to form clouds, and the clouds ultimately produce snowfall. The warmer the lake waters, the more snow that will be produced. True to form, the waters on Lake Ontario this year were warmer than usual. "This winter, there's no way the lake will freeze." Therefore, a cold snap heightens the chance of heavy snow.
A CLEAR WARMING TREND: The long-term trends present clear evidence that climate change is "real and serious." The IPCC report noted that the "the warmth of the last half century is unusual in at least the previous 1300 years." Of the 12 hottest years on record, 11 have occurred since 1995. The 2006 average annual temperature for the contiguous United States was the warmest on record and nearly identical to the record set in 1998, according to scientists at the National Oceanic & Atmospheric Administration's National Climatic Data Center. In 2006, five states had their warmest December on record (Minnesota, New York, Connecticut, Vermont, New Hampshire) and no state was colder than average. The Japan Meteorological Agency reported that January 2007 was the world's hottest January on record, with temperatures across the planet registering 0.45 degrees Celsius (0.8 degrees Fahrenheit) above average. Residents of the Washington, D.C. metropolitan area have this week been hit by a "gusty wintry wallop" and are experiencing below-average temperatures for this month. Yet, the deviation below the average temperature for February is still less than the above-average deviation that D.C. residents experienced during the month of January. While the climate change trend is clear, the weather patterns at different moments in time will be hard to predict.
great article!
ReplyDeletethanks!