Friday, May 23, 2008
Saturday, May 10, 2008
Predicting the nest solar age
Solar prediction is a problematic exercise as there are no proper physical models that allow predictions of even the next cycle. Therefore predictions tend to be based on statistical inference with little in the way of physics or modelling involved. For example, longer solar cycles tend to be followed by a weaker cycle.
The closest thing to a scientific consensus on solar prediction comes from the Solar Cycle Prediction Panel, consisting of members of NASA, NOAA, ISES and other US and International representatives. In March 2007, they released a consensus statement for the amplitude of the upcoming cycle 24. Their position:
"In light of the expected long interval until the onset of Cycle 24, the Prediction Panel has been unable to resolve a sufficient number of questions to reach a single, consensus prediction for the amplitude of the cycle. The deliberations of the panel supported two possible peak amplitudes for the smoothed International Sunspot Number (Ri): Ri = 140 ±20 and Ri = 90 ±10."
In other words, cycle 24 may be larger or smaller. The cycle is expected to begin in early 2008 and predictions are largely speculative until it begins. The one thing we do know is when Solar Cycle 24 begins, the warming sun will add to the global warming trend as it heads towards solar maximum, nearly doubling the projected temperature rise from greenhouse gases from 2008 to 2012 (Camp 2007).Lessons from past global climate changes
Proponents of CO2 as the cause of global warming have stated that "never before in the history of the earth has
climate changed as rapidly as in the past century, proving that global warming is being caused by anthropogenic
CO2" “:Our civilization has never experienced any environmental shift remotely similar to this. Today’s climate
pattern has existed throughout the entire history of human civilization” (Gore, 2006). Statements such as these are
easily refutable by the geologic record. Figure 5 shows temperature changes recorded in the GISP2 ice core from
the Greenland Ice Sheet. The global warming experienced during the past century pales into insignificance when
compared to the magnitude of at least ten sudden, profound climate reversals over the past 15,000 years. As shown
on Figure 5, the temperature in Greenland changed abruptly:
• 1. About 15,000 yrs ago, a sudden, intense, climatic warming (~12° C; ~21° F) caused dramatic melting of
large Ice Age ice sheets that covered Canada and the northern U.S., all of Scandinavia, and much of northern
Europe and Russia. Sea level that had been 120 m (~400 ft) lower than present rose quickly and submerged
large areas than had been dry land during the Ice Age.
• 2. A few centuries later, temperatures again plummeted (~11° ; ~20° F) and glaciers advanced.
• 3. About 14,000 years ago, global temperatures rose rapidly (~4.5°C; ~8° F) once again and glaciers
• 4. About 13,400 years ago, global temperatures plunged again (~8°C; ~14° F) and glaciers advanced.
• 5. About 13,200 years ago, global temperatures increased rapidly (~5°C; ~9° F) and glaciers receded.
• 6. 12,700 yrs ago global temperatures plunged sharply (~8°C; ~14° F) and a 1000 year period of glacial
readvance, the Younger Dryas, began.
• 7. 11,500 yrs ago, global temperatures rose sharply (~12° C; ~21° F), marking the end of the Younger
Dryas cold period and the end of the Pleistocene Ice Age.
• 8. 8,200 years ago, the post-Ice Age interglacial period was interrupted by a sudden global cooling (~4° C;
~7° F) that lasted for a few centuries.
• 9. About 1000 AD, global temperatures rose several degrees to begin the Medieval Warm Period, which
lasted a few centuries, then ~12300 AD dropped ~4°C (~7° F) in ~20 years.
• 10. About 1600 AD, global temperatures cooled several degrees at the beginning of the Little Ice Age,
which lasted about two centuries.
Figure 5. Abrupt global climate changes in the past 15,000 years. (Modified from Alley, 2004)
Magnitude and significance of previous global climate changes
All ten of the global climate changes described above were far more intense (12 to 15 times as intense in some
cases) than the global warming of the past century (compare them in Fig. 5), and they took place in as little as 20–
100 years. As shown on Figure 5, the global warming of the past century (0.8° C) is virtually insignificant when
compared to the magnitude of the earlier global climate changes.
Not a single one of these sudden global climate changes could possibly have been caused by human CO2 input
to the atmosphere because they all took place long before human CO2 contributions to the atmosphere began. The
cause of the ten ‘natural’ climate changes that occurred earlier could easily have been the same as the cause of
present global warming.
So are we heading to a new Little Ice Age or Maunder Minimum as it is called? There only clues. It happened in the past (1645-1710) and it will happen again to the future. I am afraid that many of us we will live so long to see what really happen. But even though, it is not a good news for amateur radio activities.