The Scientific Proposition: Global Warming

7 December 2009 | by Dr Willem de Lange

Is “Climate Change” worse than IPCC projections?

The Inter-governmental Panel on Climate Change (IPCC) is made up of three groups; a combination of activists (Greenpeace), scientists and administrators who write the actual scientific reports, government representatives (policymakers) who write the “Summary for Policymakers”, a Synthesis Report where a political interpretation is made of the science considered during the reporting process.

Since its establishment, the IPCC has produced a series of Assessment Reports (1990, 1995, 2001 and 2007). Each successive report provides a revised (downwards) prediction of the possible effect of anthropogenic greenhouse gas emissions on global temperature and sea level.

What has happened in NZ?

During the 20th century, New Zealand climate warmed 1°C and sea level rose by 0.17m. The IPCC (2007) report stated that climate change is mostly due to human activities since 1950; over the last 50 years of the 20th century New Zealand climate warmed 0.4°C and sea level rose by 0.07m i.e. at approximately the same rates as observed during the first 50 years of the 20th century.

Over the first 9 years of the 21st century, New Zealand climate has cooled 0.2°C and sea level has fallen by 0.03m despite the increasing atmospheric CO2concentration.

Carbon dioxide is a poor predictor of temperature

There is no match between atmospheric CO2 concentration and temperature (either increasing or decreasing) in the period from 1950 that the IPCC maintains the anthropogenic emission of CO2 and other greenhouse gases such as methane and nitrous oxide has caused a catastrophic increase in temperature:

Years	CO2	Methane	Nitrous Oxide	Temperature
1950 to 1975	increase	increase	increase	Decrease
1976 to 2001	Linear increase	Increase, stable since 1999	Linear increase	Increase
2002 to 2009	Linear increase	No increase (stable)		decrease

UNEP withdraws ‘hockey stick’

In 1995, the IPCC released its 5-yearly report on climate change [in a blaze of publicity], which contained the now infamous phrase that there was "a discernible human influence on global climate".

In their previous 1990 report the IPCC included this graph:

Fig.1 - Global temperature since 900 AD

The graph clearly shows the Medieval Warm Period and the Little Ice Age, both of which are clearly recorded in the historical literature of the time; the Medieval Warm Period (MWP) is suggested by the opening lines to the Canterbury Tales by Geoffrey Chaucer and the Little Ice Age (LIA) as suggested by John King.

This graph shows that temperatures during the MWP were higher than those of today while it was much cooler during the LIA. Historical records from all over Europe and Greenland attest to the reality of both events, and their profound impact on human society. For example, the colonisation of Greenland by the Vikings early in the millennium was only possible because of the medieval warmth. During the Little Ice Age, the Viking colonies in Greenland collapsed, while the River Thames in London often froze over, resulting in frequent and well-documented `frost fairs' being held on the river ice.

In 1999, a new paper published in `Geophysical Research Letters’ altered the whole landscape of how past climate history was to be interpreted by the greenhouse sciences. Dr Michael Mann of the Department of Geosciences, University of Massachusetts was the primary author of what has come to be known as the ‘Hockey Stick’ as it obliterated the MWP and the LIA and showed a dramatic upturn in temperature in the period, 1850-1998.

Fig.2 - The `Hockey Stick'

The hockey stick graph appears to show that the Earth’s climate was relatively stable from AD1000 to 1900, and then suddenly began to change, with temperatures in the Northern Hemisphere rising dramatically to 1998, a year warmed by the big El Niño of that year. This graph was central to the 2001 Third Assessment Report (TAR) of the IPCC. As soon as the TAR came out, it became gospel. The hockey stick was hotly defended and attacked by scientists on both sides of the debate. The hockey stick was inconsistent with large volumes of instrumental records such as the de Bilt in the Netherlands (temperature records since 1706) and the highly regarded 1,000 year old Chinese records.

Tree rings are the primary proxy behind the `Hockey Stick'. Tree rings are only laid during the growing season, not the whole year, and so they tell us little or nothing about annual climate. For example, 2000 was a warm winter and early spring in the north-eastern USA, followed by an unusually cool summer and autumn. Since the two events are largely self-cancelling, the year may finish as fairly average, but the tree rings would only record the cool summer and thus give a completely false impression of the full-year temperature. Tree rings do not record night temperatures since photosynthesis only occurs in the daytime. Yet winter and night temperatures are an essential component of what we understand by the concept `annual mean temperature'.

All a tree ring can tell us is whether the combined micro-environmental conditions during the growing season were favourable to tree growth or not. This is because tree rings are influenced by numerous factors other than temperature, such as rainfall, sunlight, cloudiness, pests, competition, forest fires, soil nutrients, frosts and snow duration. Thus they are not even a good daytime temperature proxy for the few months of the growing season. Other proxies such as isotopes in coral, ice, minerals and sediments are vastly superior.

Mann used Bristlecone and foxtail pine species as his proxy (closely related species). However there is evidence in the literature, that the use of the bristlecone pine series as a temperature proxy may not be valid (suppressing the "warm period" in the hockey stick handle); and that bristlecone do exhibit CO2-fertilized growth over the last 150 years (showing as enhancing warming in the hockey stick blade).

There are also a handful of other tree ring series that are nearly as common and just as influential on the results. One of the most significant of these is what is referred to as the “Yamal Data”.

The Yamal data was collected by a pair of Russian scientists in the late 1990’s, and published in 2002. In their interpretation of the data, Yamal showed little by way of a twentieth century temperature trend. Strangely though, Keith Briffa's version in Briffa's 2000 paper in Quaternary Science Reviews, which was published before the Russians', was somewhat different. While it was very similar to the Russians' version for most of the length of the record, Briffa's version had a sharp uptick at the end of the twentieth century, another hockey stick. The Yamal Data was used in the reconstructions by Mann, among others, to generate the hockey stick.

When scientists started to look at the Yamal Data, they asked Briffa for his data to see why the Russian analysis was so very different. Briffa refused and was supported by Science magazine. However in July 2008, a new Briffa paper appeared in the pages of the Philosophical Transactions of the Royal Society B, the Royal Society's journal for the biological sciences. The new paper discussed five Eurasian tree ring datasets, which, in fairly standard Hockey Team fashion, were unarchived and therefore not susceptible to detailed analysis. Among these five were Yamal and the equally notorious Tornetrask chronology. Steven McIntyre observed that the only series with a strikingly anomalous twentieth century was Yamal.

However the Royal Society had a clear and robust policy on data availability and 14 months later, McIntyre was given notice that Briffa had posted the data on his website.
But the Data was not clear. Briffa had merged a number of sites, some up to 400 km distant despite there being ample data from nearby sites.

McIntyre therefore prepared a revised dataset, replacing Briffa's selected 12 cores with the 34 from Khadyta River. The revised chronology completely removes the sharp uptick in the series at the end of the twentieth century, leaving a twentieth century without a significant temperature trend. The blade of the Yamal hockey stick, used in so many of those temperature reconstructions that the IPCC said validated Michael Mann's work, was gone.

The hockey stick has now been withdrawn from the IPCC web site in the past few months with no accompanying fanfare; removing the basis for the IPCC concern for catastrophic warming.

HadCrut and de Bilt Temperature Data

Britain’s Hadley Centre for Climate Prediction and Research (HadCrut), is part of the British Meteorological Office and one of the world’s foremost climate-monitoring sites. HadCrut’s data shows that the planet isn’t warming at the moment, and hasn’t for the past 10 years or so.

The HadCrut data clearly indicate that cooling is occurring this century; the trend of which is below the confidence limits for the IPCC’s 4th assessment report in 2007 (AR4).

Non-linear analysis of de Bilt and HadCrut temperature data shows cyclical temperature variation over various timeframes; this behaviour being consistent with solar forcing and not CO2 forcing, with variations in solar activity being the primary cause of the observed temperature trends.

Linear analysis of these data sets confirm the same rate of warming pre and post 1950, there being no significant difference between the rate of warming at the end of the 20th century and the rate of warming from 1909-1941 during a prior warming phase, that cooling (no warming) has occurred this century, and that the temperature this century is below the lower confidence limit of the IPCC AR4 temperature projections.

Solar Forcing – climate change is mainly natural

Variations in the amount of sunlight reaching the oceans will control the rate at which the oceans warm. This is influenced at long time scales by changes in the Earth’s orbit. At short time scales there are changes in the amount of sunlight associated with the sunspot cycles. These changes are small, but due to the ability of the oceans to store heat it may be possible to have a cumulative effect as sunspot cycles wax and wane. However, the main control is the amount of cloud and ice cover. Clouds and sea ice reflect sunlight before it can be absorbed by the oceans, and is referred to as albedo. Albedo changes have a greater influence on climate than the Greenhouse Effect, and are usually invoked to produce the catastrophic consequences of “Climate Change” (aka Accelerated Global Warming).

Oceans lose heat through evaporation (53%), infra-red radiation (41%) and conduction (6%). The Greenhouse Effect can slow the loss of the infra-red radiation, thereby warming the atmosphere but not the oceans. However, evaporation accounts for more than half the heat loss. Evaporation produces clouds, and hence there is a feedback loop – warming the oceans results in more evaporation, producing more clouds, which increases albedo, which cools the oceans. This is exactly what was observed during The Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment (TOGA COARE) that was set up to investigate the Pacific Warm Pool – the warmest ocean water in the western equatorial Pacific Ocean. COARE also found that rainfall would cool the ocean surface, so increased evaporation producing rain is another feedback loop.

What does this have to do with the 20th Century? Well the observed climate change is consistent with variations in albedo and associated ocean warming and cooling, suggesting that it is just a natural cycle. This pattern of behaviour is evident in palaeoclimate data for most of the last 10,000 years. None of this is simulated in climate models, which instead focus on the 20th Century increase in CO2, CH4 and a few other greenhouse gases and infer from a correlation with global temperature that the greenhouse effect is driving temperature.

However, it is also correct that changing ocean temperatures affect the concentration of these gases in the atmosphere as the solubility of these gases in water changes with water temperature. At annual and 2-7 year time scales it is clear that the concentration of CO2 in the atmosphere is strongly driven by the ocean. At longer time scales it is also clear that the atmospheric concentration of greenhouse gases lags behind, and therefore is driven by, temperature. Once again the oceans are the likely control on atmospheric greenhouse gas concentrations. The IPCC position requires that for 50-100 year periods everything works in reverse, which still show an oceanic influence at shorter time periods. It is more likely that the warming of the oceans since the Little Ice Age is a major contributor to the observed increase in CO2. Carbon isotopic ratios indicate that while there is a contribution from the burning of fossil fuels, it is of the order 1-5 percent of the observed increase in atmospheric CO2 concentration.

Storm Trends

Since many coastal hazards are affected by climate, I have been involved in researching climate variability and its effect at the coast and I have been an advisor to Civil Defence on tsunami and storm surge hazard since the mid-1980s.

IPCC policy makers often claim that there is overwhelming scientific evidence that more intense storm surges and sea-level rise along with increased cyclonic activity and heightened storm surges are expected from the rise in sea surface temperature now observed at all latitudes and in all oceans.

However data for the number of land-falling hurricanes in the United States between 1851 and 2005 shows a reduction in the magnitude and the frequency of such events.

Multi-decadal to centennial variation in storm frequency, magnitude and paths correlates best with solar frequency rather than CO2.

global_running_ace2

It is generally accepted among climate scientists that a cooler climate will produce increased storm activity as shown in the Little Ice Age historical records and that a warmer climate will produce decreased storm activity as shown below:

decadal_hurricanes

US Landfalling Hurricanes by Category and Decade 1851-2005.
Pielke et al 2008, Natural Hazards Review: 29-42

Sea Level Rise

During the 20th Century, the rate of sea level rise slowed, but with significant decadal variations.

The IPCC Summary for Policymakers (2007) stated that satellite sea level data suggest an increasing rate of sea level rise in the future. However for each of the ICCP reports the preceding projection for sea level rise has been revised downwards as follows:
1990: 0.31 - 1.10 m per century
1995: 0.20 - 0.86 m per century
2001: 0.09 - 0.88 m per century (0.31-0.49 m most likely)
2007: 0.18 - 0.59 m per century (±0.20 m uncertainty)

These projections compared with a historic trend in sea level rise of 0.15-0.20 m per century

The IPCC Second Assessment Report assessed sea level rise by AD 2100 as being in the range 0.20-0.86 m, with a most likely value of 0.49 m (less than half the rate assumed for the economic analysis). Subsequent research has demonstrated that coral atolls and associated islands are likely to increase in elevation as sea level rises. Hence, the assumptions were invalid, and I was convinced that IPCC projections were unrealistic and exaggerated the problem.
Following the release of IPCC Second Assessment Report I also co-authored the sea level rise section of the New Zealand impact report, and same section for a revised report following the release of IPCC Third Assessment Report (2001). The third report followed the trend of decreasing sea level rise projections evident in sea level rise literature, with a most likely projection of 0.44 m. However, some extreme scenarios were added at a late stage of the review process to give a wider range of projections from 0.09-0.88 m. There was little support in the literature for these extremes, and my view was that a range of 0.31-0.49 m was more reasonable. I also expected future projections to be lower.
For the New Zealand 2001 report, I was asked to state that sea level rise was accelerating, or at least could be accelerating. However, my own research and published literature shows that sea level fluctuates at decadal time scales. Therefore, although there was an increase in the rate of sea level rise around 1998, I expected sea level rise to slow and reverse early in the 21st Century. The underlying long-term trend, however, was a likely decrease in sea level, and there were some tide gauge data to indicate that it had started to do so. In the 1980s, the New Zealand rate was 1.8 mm per year. By 1990, it was 1.7 mm per year, and by 2001 it was 1.6 mm per year. These changes are small, and were not enough to prove that sea level rise was slowing. However, they clearly did not show that sea level rise was accelerating.

Satellite data used by the IPCC is in conflict with actual tide gauge data. Although the tide gauge data is more accurate, IPCC relies on the satellite data. Despite the IPCC's projections of continued sea level rise, sea levels have actually declined since 2001.

Sea Level Decrease

In New Zealand the process of subduction between 2 volcanic plates as occurs naturally in places like Whakatane, is also a more significant factor in sea level decrease than the theories around sea level rise.

After 2001, published studies continued to project lower global sea level rises over the 21st Century, and several reported a slowing of the rate of rise during the 20th Century. Shortly before the IPCC Assessment Report 4 was published I undertook a literature review of all sea level studies, which: projected lower levels than the IPCC Third Assessment Report review; indicated a slowing of the rate of sea level rise; emphasised the role of decadal scale fluctuations; and there was concern about the discrepancy between satellite and tide gauge sea level measurements. It was recognised that, although satellite sensing gives a better overall measurement of global sea level, satellites reported twice the rate of sea level rise being measured at the coast. It was evident that satellite data could not be combined with tide gauge data.

The IPCC Assessment Report 4 report (AR4) emphasises a single paper, which was not available when I conducted my review, which spliced the satellite data onto the tide gauge data to “find” acceleration in sea level rise over the period of satellite measurement. This is being used to imply that global sea level rise is accelerating due to global warming (now renamed Climate Change). The satellite data only covered the period of increasing sea level associated with decadal cycles, and the known discrepancy between satellite trends and tide gauge trends was not corrected for. This is poor science comparable to the splicing of proxy and instrument data in the infamous Hockey Stick graph, and the splicing of ice core and instrumental CO2 measurements to exaggerate the changes.

Despite therefore finding accelerating sea level rise, the latest IPCC assessment projects lower sea level rises than the previous ones. The methodology used to report the projections was changed to make comparisons harder, but the range of 0.18-0.59 m equates to a most likely rise of around 0.39 m. The IPCC AR4 also included an extra 0.20 m allowance for uncertainties associated with destabilisation of the Greenland and West Antarctic Ice Caps. Various groups have speculated that the collapse of these Ice Caps could produce a much higher additional sea level rise. In contrast, published studies that have specifically studied this contribution have concluded that given the worst possible scenarios, the maximum extra contribution is 0.18 m. Hence, the IPCC AR4 allowance is a very conservative upper bound.
What has sea level actually done so far this century? There have been large regional variations, but the global rate has slowed and is currently negative, consistent with measured ocean cooling. Claims to the contrary are unrealistic exaggerations.

Arctic Warming

Melt season air temperature have not changed for more than 50 years. Air temperature data show that 1935 was the warmest year in the Arctic. These data were presented in a study by Arctic scientist Igor Polyakov, who also showed that the warmest period in the Arctic was from the 1930s through to the 1940s.

A new Arctic study published by Håkan Grudd, of Stockholm University’s Department of Physical Geography and Quaternary Geology, confirms the conclusion that the Arctic is not warmer now than it was previously.

He states: “The late twentieth century is not exceptionally warm in the new Torneträsk record. On decadal to centurial timescales, periods around AD750, 1000, 1400, and 1750 were all equally warm, or warmer.”

In addition, Danish Metrological Institute records show that the “Arctic was warmer in the 1940s than now” – this was published May 13, 2009.

Warming in the arctic is predominantly at night (during the long arctic winter when there is no sunlight) and is not consistent with the Greenhouse Effect or Ice-Albedo effect.
There is a correlation between arctic warming and ocean circulation Atlantic Multidecadal Oscillation (AMO) highlighting the importance of ocean currents in determining air temperature in the arctic.

Sea Ice

Sea ice extent varies seasonally and is affected by such factors as:

Ocean circulation
Atmosphere circulation
Ocean temperature
Air temperature

Trends in the extent of sea ice have varied between hemispheres since 1980 when satellite measurement of sea ice area became available. The area of arctic sea ice has been decreasing at an average rate of 11.2% per decade since 1980 but is now increasing. The area of Antarctic sea ice has been increasing at an average rate of 0.7% per decade since 1980 despite the loss part of the western ice shelf. The total area of sea ice (sum of Arctic and Antarctic sea ice) is now mid-way between the low measured in 2007 and the high measured in 2003. This observation is suggestive of natural variation and confirms that there is not an increasing trend of sea ice loss as predicted by the IPCC.

Ocean Acidification

The words oceans are alkaline i.e. they have a pH of greater than 7.0. The lowest pH occurs where oceans release CO2, (in the warm equatorial waters) whilst the highest pH occurs where oceans are absorbing CO2 (in the colder waters of the arctic and antarctic). The maximum measured pH reduction (0.1pH units) attributable to CO2 absorbtion is less than natural diurnal variability of oceanic pH caused by the release of CO2 by plankton respiration during darkness.

Sun and Climate

Variations in the intensity and composition of energy from the sun, the primary source of heat for the earth, can be expected to have a significant effect on the earth’s climate – as typified by the seasonal changes in temperature.

Total Solar Irradiance (TSI), or visible light travels through the atmosphere without any effect and is absorbed by the ocean resulting in warming. The 0.1% variation in TSI experienced over the11 year Schwabe cycle and the larger variations in TSI experienced over longer periods (>0.3%) can be expected to result in variations ocean warming and temperature over decadal and multidecadal timeframes.

Variations in UV intensity of the order of 1-3% typically occur over decadal and multidecadal time frames. These affect the stratosphere, and TSI reaching the earth surface.

Variation in solar cycle length also affects the energy reaching the earth surface; with shorter cycles resulting in warming and longer cycles resulting in cooling. The current sun cycle (Cycle 23) is the longest since 1700s and would be expected to be associated with cooling.

Variations in the sun geomagnetic intensity is evidenced in isotope data (14C and 10Be) and is linked to cloud formation via cosmic ray flux.

Oceans

The earth is approximately 70% ocean. The oceans gain heat from solar short-wave radiation (radiant energy) and geothermal heat flow. They obtain negligible heat input by conduction from atmosphere (negligible greenhouse effect). They loose heat to the atmosphere by evaporation (clouds), infra-red radiation and conduction.

Oceans have a very large thermal mass and store more heat than the atmosphere and are observed to be warming at same rate & time as atmosphere. This heat is stored and transported in different layers & is stored for variable lengths of time.

The Future

So far this Century measured climate change is not worse than IPCC projections. The Greenhouse Effect is not the dominant driver of climate change. It is likely that global cooling will continue for next 20-30 years, change beyond that point is very uncertain. The Sun may be heading into another Dalton or Maunder minimum, with sunspots potentially disappearing by 2015.

The authoritative SPPI composite index of global mean surface temperature anomalies, taking the mean of two surface and two satellite datasets and updated through November 2008, shows a pronounced downtrend for eight full years. Not one of the climate models relied upon by the IPCC had predicted this downturn.