In my last two columns, I said there have been mild global temperature increases for some time, much apparently from increasing carbon-dioxide (CO2) levels in the atmosphere, and much of that human-caused. However, earth has had much higher CO2 levels in the past. And in recorded history, we’ve seen significant warming and cooling cycles.
Also, projecting temperatures into the future relies on complex computer models with feedback loops, guesstimates of key parameter values, major temperature measurement problems, and large doses of judgment. These exercises don’t have a good track record.
The key debates between climate alarmists and skeptics are the issues of impacts of warming that may occur and the need for and effects of proposed remedies, not whether there’s been some warming.
I also presented key climate-change facts found at the Heartland Institute’s web site, email@example.com, including the lack of warming in recent years in the U.S. and the decline in the number and severity of tornadoes and droughts. Today, more of those facts.
Warming lengthens growing seasons, and delivers more precipitation, fewer frost events and more CO2 (an aerial fertilizer) to plants. So, in America and around the world, these benefits of warming add to the effects of technological progress to continuously increase crop yields and improve diets and health. Also, increased precipitation lowers drought levels.
Heartland states: “There has been no evidence of increased flooding frequency or severity as the climate modestly warms.” They cite findings of the Intergovernmental Panel on Climate Change (IPCC) and academic studies that come to the same conclusion.
Average Northern Hemisphere snowpack data exist since 1966, and they show increasing trends for both fall and winter months. After a brief decline in the 1980s, North American snowpack has been on an uptrend, while Asian and European levels have shown a slight decrease.
Heartland states there’s been no increase in hurricanes as the planet has modestly warmed. The IPCC agrees, finding no increase in the frequency or severity of tropical cyclones. In 2005-17, the U.S. experienced its longest ever period without a major (category three or higher) hurricane, and in 2009-17 we had the fewest hurricanes of any eight-year period. Florida, our most hurricane-vulnerable state, in 2005-16 had no hurricanes of any size – its longest such period in history.
Heartland notes some global warming activists claim modestly warmer global ocean temperatures are “supercharging” the storms. But those ideologues studiously ignore that such warming also increases wind shear that inhibits strong storms from forming and tears apart those that have already formed. Hence, no increase in hurricane frequency and severity.
Global sea levels have been rising about a foot per century since at least 1860. NASA satellite measurements since 1993 show acceleration of that figure by 0.3 inches per decade, raising the current increase rate to 1.5 inches per decade. Isolated sites with higher-level rises reflect local conditions, such as tectonic plate movement and withdrawing underground fresh water reserves.
Global climate change alarmists and their mainstream media allies claimed during a recent short-term decline in Great Lakes water levels that a new normal had arrived. In 2013, Think Progress said, “Several different climate models for the Great Lakes region all predict that lake levels will decline over the next century.” Since 2014, the lakes have sustained levels abundantly above historic averages and have reached their highest levels ever recorded.
Heartland observes: “As often happens, alarmists claimed a climate crisis had arrived, only to be proven wrong yet again.”
Lake Mead water levels rose steadily to record heights in 1965-83 and remained above average through 2002, even as average temperatures rose. In recent years, the Colorado River basin has seen below-average precipitation while most of the nation has enjoyed increasing precipitation, as even the IPCC has noted. Heartland notes: “One cannot blame global warming for the few areas of below-average precipitation that remain.”
Also important to Nevada, the 2015-16 northern California drought dropped Lake Tahoe levels by about seven feet from 2011 levels, and alarmists claimed a “new normal” of low levels caused by climate change. Since then, Lake Tahoe has reached its maximum allowable limit of nine feet above gage height each year, over seven feet above the 2016 levels.
More next time.