The Real Cause of Climate Change

Is it CO2 increase or solar irradiance fluctuations?

Why do IPCC model predictions fail to fit recent observation of global cooling?

For a biblical perspective see: It's God's Weather

For the government perspective see: IPCC Climate Predictions

Forecasts from the Sun

Piers Corbyn has a first-class degree in astrophysics and operates as a meteorologist in London. He makes weather forecasts based upon the sun's irradiance and how it interacts with the upper atmosphere. He claims 85% accuracy in his forecasts - including the cold, snowy December of 2010 in the UK. Piers says: "The next 30 years will see Arctic ice expand as we head into the new Little Ice Age."

A Cooler Europe

Since 1979 the Autumn levels of Arctic sea ice have declined by 30% [National Academy of Sciences, USA]. This loss of ice can affect atmospheric circulation patterns and weaken westerly winds in the North Atlantic (resulting in 'blocking patterns'). In turn this could allow more frequent northerly winds into Europe, with corresponding increase in snowfall. Ice loss could lead to similar cooling in the NE and Midwestern U.S.

Related topics:
End Times
It's God's weather

Glacier shortening

Fig.2: Glacier Shortening

Sea level rise

Fig.3: Sea Level Rise

Greenland Ice Sheet Temperatures

Fig.4: Greenland Ice Sheet Air Temperature

Image courtesy Climate4you (Alley, 2000)

Correlation of solar irradiance with temperature

Fig.7: Solar Irradiance and Temperature

Correlation of solar irradiance with temperature

Fig.8: Solar Irradiance and Temperature

Images courtesy B. Robinson, N. Robinson,
and W. Soon Global Warming Petition Project

Correlation of solar cycle length with temperature

Fig.9: Solar Cycle Length (yrs) and Temperature Anomaly

Image based on Friis-Christensen and Lassen

Global Sea Surface Temperatures

Fig.12: Monthly Mean Global SST

Image courtesy NASA GISS

What Causes Climate Change?

Few scientists dispute that climate change is really happening. The central question is "What is causing it"? The official scientific view (that of the Intergovernmental Panel on Climate Change, IPCC) is that warming over the past 50 years is largely anthropological i.e. man-induced due to the burning of fossil fuels, and that such burning must be curbed to avoid catastrophic effects:

"Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas (GHG) concentrations." [IPCC AR4, 2007]

The science behind such a statement essentially assumes strong correlation between CO2 and temperature, as in Fig.1:

CO2 and temperature

Fig.1: CO2 and temperature (GISS data)

Image courtesy Skeptical Science

The poor correlation between 1940 and 1975 (CO2 rising, temperature falling) is attributed to the fact that CO2 is not the only contributer to warming (see Skeptical Science). But correlation does not imply 'causality' i.e. it does not imply that CO2 rise causes temperature rise. In fact, some claim that CO2 rise naturally follows, and probably results from, increases in temperature - not the other way around.

Correlation and Causality Issues

Glacier Retreat: CO2 rise is poorly correlated with glacier retreat. It is claimed that glacier retreat is largely a result of warming from CO2 rise. But Fig.2 (opposite) shows that glaciers started retreating around 1820 i.e. warming started around 1800, some 150 years before significant CO2 emissions commenced in 1950. And note that the retreating rate does not increase after 1950 (as might be expected if it was due to CO2 increase). Glaciers advance and retreat naturally and their current behaviour is not abnormal. It seems CO2 rise is not a primary cause of glacier retreat.

Sea Level Rise: Similarly, it is claimed that sea level rise is strongly linked to warming from CO2 rise. But sea levels have been rising at an averaged rate of 7 inches per century or 1.8mm per year since about 1860 - well before any CO2 induced warming (Fig.3). Also, sea level rises partly because of the expansion of warmer water, but sea surface temperatures in the North Atlantic have been increasing since 1700 (since the 'Little Ice Age') and currently they are only at the mean value for the last 3,000 years (J. Bluemle, 1999)! It seems CO2 rise is not a primary cause of sea level rise.

Greenland Temperatures: Figure 4 shows the air temperature at the summit of the Greenland Ice Sheet, reconstructed by Alley (2000) from GISP2 ice core data. The temperatures tend to reflect global temperature changes over the past 6,000 years (up to 1855 AD) and show several warm periods (green), including the current one. Despite the warm periods, there is a clear cooling trend over the last 4000 years. The significant point here is that over the same 4,000 year period the CO2 concentration showed a steady rise. It seems that CO2 is negatively correlated with Greenland temperatures over this time span.

Global Temperatures: Figure 5 shows global monthly surface air temperatures and atmospheric CO2 (March 1958 - June 2013). Clearly, over this period there are two distinct periods when CO2 was negatively correlated with temperature. And note that since 2002 global temperatures have been falling despite CO2 reaching 400 ppm.

The weak correlation of CO2 with temperature

Fig.5: The weak correlation of CO2 with temperature (NOAA NCDC data)

Image courtesy Climate4you

Medieval Temperatures: Poor correlation between CO2 and temperature is also found in recent history. For example, the CO2 levels c1000 AD were significantly lower than present-day levels despite higher temperatures, and they did not significantly decrease during the 'Little Ice Age' c1600 AD. In addition, from 1957-2000 the South Pole temperature decreased by 1.5 deg whilst the corresponding CO2 rose from 314 to 360 ppm.

Poor Model Predictions: The IPCC, NASA GISS, UK Met Office and others claim recent warming is largely man-induced (anthropological), and predictions from their models are shown in Fig.6:

IPCC AR5 averaged surface temperature

Fig.6: IPCC AR5 averaged surface temperature °C

Image in Public Domain

Figure 6 shows observed globally and annually averaged surface temperature (°C) since 1990 compared with the temperature projections from previous IPCC assessments. Values are aligned to match the average observed value at 1990. Observed global annual temperature change, relative to 1961-1990, is shown as black squares. But the observed temperatures are very near or below the low end projections of IPCC report AR4 (2007)! Are the models wrong?

Conclusion: Many claim that there is little CO2-temperature correlation e.g. Fig.5. If so, there is little or no causality (CO2 rise is not the principal cause of temperature rise, glacier retreat, or sea level rise); in fact, a CO2 rise sometimes lags warming by hundreds of years. Add to this poor IPCC model predictions and we are led to ask "Is there another major player in climate change?" Is the observed warming over the last century largely due to a natural recovery from the Little Ice Age (or indeed from the one and only ice age of a young earth). If so, what is the principal climate changing mechanism - the sun perhaps?

Effect of Solar Irradiance Changes

Solar irradiance is the solar power per unit area falling on the earth (in W/square metre). The sun's irradiance fluctuates constantly in conjunction with the sunspot number, which varies over an approximate 11 year cycle. The total solar irradiance (TSI) is larger during the portion of the 11 year cycle when there are more sunspots. Solar cycle 24 peaked around 2013 and cycle 25 is expected to peak around 2025.

What observed evidence is there that global temperatures are correlated with solar irradiance? Consider the scientific measurements in Fig.7 and Fig.8. It is clear from both graphs that temperature correlates well with solar irradiance even after industrialisation started in earnest around 1900. Moreover, world hydrocarbon use started rising sharply around 1950 whilst temperatures actually fell between 1940 and 1975 following reduced solar irradiance (more detail in Fig.5)!

Good correlation was also found by Friis-Christensen and Lassen, 1991 when they graphed solar cycle length against temperature, Fig.9. The significance of solar cycle length is not to be underestimated. It is claimed at Global Warming and the Climate that solar cycle 23 was extended considerably to about 12.7 years, and this might translate to a global temperature drop of 1.2 °C by 2020. Similar high correlation with cycle length over 1880-2006 is found at Strum, which suggests a 1 °C drop in temperature in the coming decade.

On the theoretical side, a significant link between global surface temperature (GST) and total solar irradiance (TSI) has been shown statistically [Scafetta and West, Physics Today, March 2008]. Specifically, the time distribution between solar events e.g. flares is the same as that for global temperature fluctuations! The authors comment: "the sun is influencing climate significantly more then the IPCC (2007) report claims.". Their comments are supported by other theorists:

"CO2 is not responsible for heating the earth, the cause is the activity of the sun. The movement of the sun affects temperature, which influences the levels of CO2, and these levels have risen and fallen for centuries." [Professor Emeritus Giora Shaviv, professor of physics and the Swartzmann-Medvedi chair in Space Sciences at The Technion in Haifa].

So Is Solar Irradiance Reduction Causing Global Cooling?

If global temperatures correlate better with solar irradiance than with CO2, then solar activity should be studied for future climate prediction, rather than CO2. Low sunspot activity correlates with lower temperatures e.g. during the 17th century Maunder Minimum, sunspots were rare and the northern hemisphere experienced the "Little Ice Age". Between 1790 and 1820, a minor decline in solar activity called the Dalton Minimum also correlated with lower global temperatures. This sunspot low is shown in Fig.10.

Sunspot activity

Fig.10: Sunspot Activity (red line is running 11 year average)

Image courtesy SIDC, (Solar Influences Data Analysis Center)

Global Cooling

Fig.11: Global Cooling

Image courtesy ICECAP

Figure 10 also shows that the sun has declined in activity since about 2002, and it reached a very low value in 2009. Was there global cooling? Yes. Figure 11 shows there has been a slight fall in mean global sea surface temperature (SST) since 2002, with current temperatures approaching 1990 levels. And NASA GISS, RSS MSU, UAH AMSU and Hadley data (Fig. 12) show a definite global SST cooling since 2002 (the peak is the 1997-98 "El Niņo of the century").

Such cooling is discussed in Zbigniew Jaworowski, where it is pointed out that none of the climate models relied upon by the IPCC had predicted this cooling. Some members of the Russian Academy of Sciences say we may be at the start of a period like the Dalton Minimum. They estimate that the Sun's reduced activity may cause a global temperature drop of 1.5 °C by 2020. Some claim that reduced activity affects Earth's atmosphere which in turn creates more cload cover - reflecting away solar power. Many expect solar cycle 25 (peaking at around 2025) to show very low solar activity - see Solar forecast.

To counter the solar irradiance theory, a UK Met Office study claims that:

"... although solar output is likely to reduce over the next 90 years this will not substantially delay expected increases in global temperatures caused by greenhouse gases. The study found that the expected decrease in solar activity would only most likely cause a reduction in global temperatures of 0.08 °C. This compares to an expected warming of about 2.5 °C over the same period due to greenhouse gases (according to the IPCC B2 scenario). In addition the study also showed that if solar output reduced below that seen in the Maunder Minimum - a period between 1645 and 1715 when solar activity was at its lowest observed level - the global temperature reduction would be 0.13C." [UK Met Office, Jan 2012].

Cooling Prediction based on Solar Irradiance

Despite Met Office and IPCC claims for CO2, recent evidence suggests otherwise. There are many recent cooling examples from record low temperatures to ocean cooling. See also Global Temperatures. A theory that accurately predicts current weather events and predicts future cooling is based upon solar irradiance change - see WeatherAction. The theory utilises solar activity (eruptions), magnetic clouds in the solar wind and lunar effects to predict world weather. And, as suggested above, it totally discredits the CO2 warming theory.

So, the official (IPCC) line on global warming may be misleading. Why?