A new paper claims that declining solar activity since 1998 could mean falling global temperatures in the years ahead — contrary to predictions of rapid warming made by virtually all climate models.
“The stagnation of temperature since 1998 was caused by decreasing solar activity since 1998,” wrote Jürgen Lange Heine, a physicist with the German-based European Institute for Climate and Energy (EIKE).
“From 1900 to 1998, solar radiation increased by 1.3 W / m², but since 1998 it has diminished, and could reach values similar to those of the early 20th century. A drop in global temperature over the next few years is predicted,” Heine wrote.
Heine argues that warming during the 20th Century was not caused by increasing carbon dioxide emissions, but instead by increasing solar activity, changes in cloud cover caused by cosmic rays and huge amounts of cloud condensation nuclei in the atmosphere from the nuclear weapons tests conducted from 1945 to 1963.
Climate scientists have attributed this warming largely to carbon dioxide emissions emitted from human activities, mainly from burning fossil fuels, but Heine says the connection between carbon dioxide and temperature is only superficial.
“Despite steadily rising carbon dioxide levels observed in the years 1945 to 1975, as well as since 1998, a decrease or stagnation in global temperatures occurred that does not fit with the carbon dioxide hypothesis,” Heine wrote.
The “stagnation” in global temperatures since 1998 Heine refers to is known as the “pause” or “hiatus” in global warming. Both satellite-derived and surface temperature readings show no significant warming trend in global temperatures for the last 10 to 20 years.
Heine is not the first researcher to tie the “pause” in warming to declining solar activity. Several researchers over the years have predicted that declining solar activity could plunge the Earth into another “Little Ice Age.”
Shrinivas Aundhkar, director of India’s Mahatma Gandhi Mission at the Centre for Astronomy and Space Technology, recently told people attending a lecture that declining solar activity could mean a “mini ice age-like situation” is nigh.
“The sun undergoes two cycles that are described as maximum and minimum,” Aundhkar said. “The activity alternates every 11 years, and the period is termed as one solar cycle. At present, the sun is undergoing the minimum phase, reducing global temperatures.”
High sunspot activity has been associated with periods of warming on the Earth, like the period between 1950 and 1998. On the other hand, low sunspot activity has been linked to cooler periods, like the so-called “Little Ice Age” when temperatures were much cooler than today.
Scientists have struggled to explain why global temperatures have not risen nearly as fast as climate models predicted. Researchers have offered dozens of explanations as to why global temperatures have stagnated since 1998.
A recent study by Pennsylvania State University climate scientist Michael Mann, a noted environmentalist and creator of the “hockey stick” graph, claims that man-made global warming is on the rise but is being tempered by natural cooling cycles from the oceans.
“We know that it is important to distinguish between human-caused and natural climate variability so we can assess the impact of human-caused climate change on a variety of phenomena including drought and weather extremes,” Mann said in a statement. “The North Atlantic and North Pacific oceans appear to be drivers of substantial natural, internal climate variability on timescales of decades.”
“Our findings have strong implications for the attribution of recent climate changes,” he said. “Internal multidecadal variability in Northern Hemisphere temperatures likely offset anthropogenic warming over the past decade.”
Other research suggests that warming has stalled because increasing amounts of carbon dioxide are being absorbed by the world’s oceans, which is causing them to warm and acidify.
A recent study published in the journal Nature found that most of the excess heat from carbon dioxide has been trapped in the tropical southern oceans. Researchers said the top 1,600 feet of ocean water warmed 0.009 degrees Fahrenheit. The next 4,000 feet warmed just 0.0036 degrees since 2006.
But the study also illustrates how the ocean is able to absorb lots of carbon dioxide, or heat, without experiencing much warming.