Going cool on climate change




The latest UN climate report is out and being hyped and exaggerated by daily news media. But keeping the IPCC honest is the NIPCC, the independent scientific body that has released its own climate report based on the latest peer-reviewed science. Here are the highlights from its Summary for Policymakers:



Summary of NIPCC’s Findings[i]


Atmospheric carbon dioxide (CO2) is a mild greenhouse gas that exerts a diminishing warming effect as its concentration increases. Doubling the concentration of atmospheric CO2 from its pre-industrial level, in the absence of other forcings and feedbacks, would likely cause a warming of ~0.3 to 1.1°C, almost 50% of which must already have occurred.

A few tenths of a degree of additional warming, should it occur, would not represent a climate

crisis. Model outputs published in successive IPCC reports since 1990 project a doubling of CO2 could cause warming of up to 6°C by 2100. Instead, global warming ceased around the end of the twentieth century and was followed (since 1997) by 16 years of stable temperature.

Over recent geological time, Earth’s temperature has fluctuated naturally between about +4°C and -6°C with respect to twentieth century temperature. A warming of 2°C above today, should it occur, falls within the bounds of natural variability.

Though a future warming of 2°C would cause geographically varied ecological responses, no evidence exists that those changes would be net harmful to the global environment or to human well-being.

At the current level of ~400 ppm we still live in a CO2-starved world. Atmospheric levels 15 times greater existed during the Cambrian Period (about 550 million years ago) without known adverse effects.

The overall warming since about 1860 corresponds to a recovery from the Little Ice Age modulated by natural multidecadal cycles driven by ocean-atmosphere oscillations, or by solar variations at the de Vries (~208 year) and Gleissberg (~80 year) and shorter periodicities.

Earth has not warmed significantly for the past 16 years despite an 8% increase in atmospheric CO2, which represents 34% of all extra CO2 added to the atmosphere since the start of the industrial revolution.

CO2 is a vital nutrient used by plants in photosynthesis. Increasing CO2 in the atmosphere “greens” the planet and helps feed the growing human population. No close correlation exists between temperature variation over the past 150 years and human related CO2 emissions. The parallelism of temperature and CO2 increase between about 1980 and 2000 AD could be due to chance and does not necessarily indicate causation.

The causes of historic global warming remain uncertain, but significant correlations exist between

climate patterning and multidecadal variation and solar activity over the past few hundred years. Forward projections of solar cyclicity imply the next few decades may be marked by global cooling rather than warming, despite continuing CO2 emissions.




IPCC’s Three Lines of Argument


IPCC modelers assume Global Climate Models (GCMs) are based on a perfect knowledge of all climate forcings and feedbacks. They then assert:

  • • A doubling of atmospheric CO2 would cause warming of up to 6°C.
  • • Human-related CO2 emissions caused an atmospheric warming of at least 0.3°C over the past 15 years.
  • • Enhanced warming (a “hot spot”) should exist in the upper troposphere in tropical regions.
  • • Both poles should have warmed faster than the rest of Earth during the late twentieth century.



Postulates are statements that assume the truth of an underlying fact that has not been independently confirmed or proven. The IPCC postulates:

  • • The warming of the twentieth century cannot be explained by natural variability.
  • • The late twentieth century warm peak was of greater magnitude than previous natural peaks.
  • • Increases in atmospheric CO2 precede, and then force, parallel increases in temperature.
  • • Solar forcings are too small to explain twentieth century warming.
  • • A future warming of 2°C or more would be net harmful to the biosphere and human wellbeing.



Circumstantial evidence does not bear directly on the matter in dispute but refers to circumstances from which the occurrence of the fact might be inferred. The IPCC cites the following circumstantial evidence it says is consistent with its hypothesis:

  • • Unusual melting is occurring in mountain glaciers, Arctic sea ice, and polar icecaps.
  • • Global sea level is rising at an enhanced rate and swamping tropical coral atolls.
  • • Droughts, floods, and monsoon variability and intensity are increasing.
  • • Global warming is leading to more, or more intense, wildfires, rainfall, storms, hurricanes, and other extreme weather events.
  • • Unusual melting of Boreal permafrost or sub-seabed gas hydrates is causing warming due to methane release.




Key Facts about Temperature Forcings and Feedbacks[ii]

A doubling of CO2 from pre-industrial levels (from 280 to 560 ppm) would likely produce a temperature forcing of 3.7 Watts per square metre (W/m2) in the lower atmosphere, for about ~1°C of prima facie warming.

IPCC models (computer simulations) stress the importance of positive feedback from increasing water vapor and thereby project warming of ~3-6°C, whereas empirical (actual observational) data indicate an order of magnitude less warming of ~0.3-1.0°C.

In ice core samples, changes in temperature precede parallel changes in atmospheric CO2 by several hundred years; also, temperature and CO2 are uncoupled through lengthy portions of the historical and geological records; therefore CO2 cannot be the primary forcing agent for most temperature changes.

Atmospheric methane (CH4) levels for the past two decades fall well below the values projected by the IPCC in its Assessment Reports. The IPCC’s temperature projections incorporate these inflated CH4 estimates and need downward revision accordingly.

The melting of permafrost or submarine gas hydrates is not likely to emit dangerous amounts of methane at current rates of warming.

Nitrous oxide (N2O) emissions are expected to fall as CO2 concentrations and temperatures rise, indicating it acts as a negative climate feedback. Other negative feedbacks on climate sensitivity that are either discounted or underestimated by the IPCC include increases in low-level clouds in response to enhanced atmospheric water vapor, increases in ocean emissions of dimethyl sulphide (DMS), and the presence and total cooling effect of both natural and industrial aerosols.




Lack of Evidence for Rising Temperatures

The difference in surface temperatures between 1942–1995 and 1979–97, as registered by

datasets that represent land, oceanic, and atmospheric locations.


United States (GISS) ~zero

OCEAN Sea surface temperature (SST)1 ~zero

SST Hadley NMAT ~zero

ATMOSPHERE Satellite MSU (1979–1997) ~zero

Hadley radiosondes (1979–97) ~zero

PROXIES Mostly land surface temperature2 ~zero

Unless otherwise indicated, data is drawn from the nominated government agencies.

1Gouretski et al., GRL, 2012; 2Anderson et al., GRL, 2013.





Key Facts about Global Climate Models[iii]

Climate models project an atmospheric warming of at least 0.3°C over the past 15 years; but in fact, temperature stasis or slight cooling has occurred.

Climate models project an ocean warming of at least 0.2°C since 2000; but in fact, no warming is observed.

Climate models project the appearance of an upper troposphere hot-spot in tropical regions; but in fact none is observed.

Climate models project late twentieth century warming should have occurred towards both poles; in fact, warming was confined to north polar regions.

Climate models generally assume a climate sensitivity of 3°C for a doubling of CO2 above preindustrial values, whereas meteorological observations are consistent with a sensitivity of 1°C or less.

Climate models underestimate surface evaporation caused by increased temperature by a factor of 3, resulting in a consequential underestimation of global precipitation. Climate models also represent aerosol-induced changes in infrared (IR) radiation inadequately, despite studies showing different mineral aerosols (for equal loadings) can cause differences in surface IR flux between 7 and 25 W/m2.

Deterministic climate models have inherent properties that make dynamic predictability impossible; introduction of techniques to deal with this (notably parameterization) introduces bias into model projections.

Limitations in computing power restrict climate models from resolving important climate processes; low resolution models (accurate to within tens of kilometres rather than tens or hundreds of metres) fail to capture many important regional and lesser-scale phenomena such as clouds.

Model calibration is faulty, as it assumes all temperature rise since the start of the industrial revolution has resulted from human CO2 emissions; in reality, major human-related emissions commenced only in the mid-twentieth century.

Non-linear climate models exhibit chaotic behavior. As a result, individual simulations (“runs”) may show differing trend values. Internal climate oscillations (AMO, PDO, etc.) are major features of the historic temperature record; climate models do not even attempt to simulate them.

Similarly, climate models fail to incorporate the effects of variations in solar magnetic field or in the flux of cosmic rays, both of which are known to significantly affect climate.






Key Facts about Surface Temperature[iv]

Whether today’s global surface temperature is seen to be part of a warming trend depends upon the time period considered. Over (climatic) time scales of many thousand years, temperature is cooling; over the historical (meteorological) time scale of the past century temperature has warmed. Over the past 16 years, there has been no net warming despite an increase in atmospheric CO2 of 8% – which represents 34% of all human-related CO2 emissions released to the atmosphere since the industrial revolution.

Given an atmospheric mixing time of ~1 year, the facts just related represent a test of the dangerous warming hypothesis, which test it fails.

Based upon the HadCRUT dataset favored by the IPCC, two phases of warming occurred during the twentieth century, between 1910–1940 and 1979–2000, at similar rates of a little over 1.5°C/century. The early twentieth century warming preceded major industrial carbon dioxide emissions, and must be natural; warming during the second (prima facie, similar) period might incorporate a small human-related carbon dioxide effect, but warming might also be inflated by urban heat island effects.

Other temperature datasets fail to record the late twentieth century warming seen in the HadCRUT dataset (Talking Point 3). There was nothing unusual about either the magnitude or rate of the late twentieth century warming pulses represented on the HadCRUT record, both falling well within the envelope of known, previous natural variations.

No empirical (real observational) evidence exists to support the assertion that a planetary warming of 2°C would be net ecologically or economically damaging.





Key Facts about Solar Forcing[v]

Evidence is accruing that changes in Earth’s surface temperature are largely driven by variations in solar activity. Examples of solar-controlled climate change epochs include the Medieval Warm Period, Little Ice Age and Early Twentieth Century (1910–1940) Warm Period.

The Sun may have contributed as much as 66% of the observed twentieth century warming, and perhaps more. Strong empirical correlations have been reported from all around the world between solar variability and climate indices including temperature, precipitation, droughts, floods, streamflow, and monsoons.

IPCC models do not incorporate important solar factors such as fluctuations in magnetic intensity and overestimate the role of human-related CO2 forcing. The IPCC fails to consider the importance of the demonstrated empirical relationship between solar activity, the ingress of galactic cosmic rays, and the formation of low clouds.

The respective importance of the Sun and CO2 in forcing Earth climate remains unresolved; current climate models fail to account for a plethora of known Sun-climate connections. The recently quiet Sun and extrapolation of solar cycle patterns into the future suggest a planetary cooling may occur over the next few decades.





Key Facts about the Cryosphere[vi]


Satellite and airborne geophysical datasets used to quantify the global ice budget are short and the methods involved in their infancy, but results to date suggest both the Greenland and Antarctic Ice Caps are close to balance.

Deep ice cores from Antarctica and Greenland show climate change occurs as both major glacial-interglacial cycles and as shorter decadal and centennial events with high rates of warming and cooling, including abrupt temperature steps.

Observed changes in temperature, snowfall, ice flow speed, glacial extent, and iceberg calving in both Greenland and Antarctica appear to lie within the limits of natural climate variation. Global sea-ice cover remains similar in area to that at the start of satellite observations in 1979, with ice shrinkage in the Arctic Ocean since then being offset by growth around Antarctica.

During the past 25,000 years (late Pleistocene and Holocene) glaciers around the world have fluctuated broadly in concert with changing climate, at times shrinking to positions and volumes smaller than today. This fact notwithstanding, mountain glaciers around the world show a wide variety of responses to local climate variation, and do not respond to global temperature change in a simple, uniform way.

Tropical mountain glaciers in both South America and Africa have retreated in the past 100 years because of reduced precipitation (often caused by deforestation to clear land for farms at the base of mountains like Kilimanjaro, which reduces the amount of moisture in the local atmosphere and hence a reduction in snowfall – Ed.) and increased solar radiation; some glaciers elsewhere also have retreated since the end of the Little Ice Age.

The data on global glacial history and ice mass balance do not support the claims made by the IPCC that CO2 emissions are causing most glaciers today to retreat and melt.





Key Facts about the Hydrosphere[vii]


Knowledge of local sea-level change is vital for coastal management; such change occurs at widely variable rates around the world, typically between about +5 and -5 mm/year.

Global (eustatic) sea level, knowledge of which has only limited use for coastal management, rose at an average rate of between 1 and 2 mm/year over the past century. Satellite altimeter studies of sea-level change indicate rates of global rise since 1993 of over 3 mm/year, but complexities of processing and the infancy of the method precludes viewing this result as secure.

Rates of global sea-level change vary in decadal and multidecadal ways and show neither recent acceleration nor any simple relationship with increasing CO2 emissions.

Pacific coral atolls are not being drowned by extra sea level rise; rather, atoll shorelines are affected by direct weather and infrequent high tide events, ENSO sea level variations, and impacts of increasing human populations (many islands have mined their reefs for coral sand to build roads, and reef destruction has removed the protective barrier against ocean surges, hastening erosion – Ed.).

Extra sea-level rise due to heat expansion (thermosteric rise) is also unlikely given that the Argo buoy network shows no significant ocean warming over the past 9 years (Knox and Douglass, 2010).

Though the range of natural variation has yet to be fully described, evidence is lacking for any recent changes in global ocean circulation that lie outside natural variation or were forced by human CO2 emissions.


Monsoons, Droughts, and Floods

Little evidence exists for an overall increase in global precipitation during the twentieth century independent of natural multidecadal climate rhythmicity. Monsoon precipitation did not become more variable or intense during late twentieth century warming; instead, precipitation responded mostly to variations in solar activity.

South American and Asian monsoons were more active during the cold Little Ice Age and less active during the Medieval Warm Period. Neither global nor local changes in streamflow have been linked to CO2 emissions.

The relationship between drought and global warming is weak, since severe droughts occurred during both the Medieval Warm Period and the Little Ice Age.





Key Facts about Extreme Weather Events[viii]

Air temperature variability decreases as mean air temperature rises, on all time scales. Therefore the claim that global warming will lead to more extremes of climate and weather, including of temperature itself, seems theoretically unsound; the claim is also unsupported by empirical evidence.

Although specific regions have experienced significant changes in the intensity or number of extreme events over the twentieth century, for the globe as a whole no relationship exists between such events and global warming over the past 100 years.

Observations from across the planet demonstrate that droughts have not become more extreme or erratic in response to global warming. In most cases, the worst droughts in recorded meteorological history were much milder than droughts that occurred periodically during much colder times.

There is little to no evidence that precipitation will become more variable and intense in a warming world, indeed some observations show just the opposite.

There has been no significant increase in either the frequency or intensity of stormy weather in the modern era. Despite the supposedly “unprecedented” warming of the twentieth century, there has been no increase in the intensity or frequency of tropical cyclones globally or in any of the specific ocean basins.



Few scientists deny that human activities can have an effect on local climate or that the sum of such local effects could hypothetically rise to the level of an observable global signal. The key questions to be answered, however, are whether the human global signal is large enough to be measured and if it is, does it represent, or is it likely to become, a dangerous change outside the range of natural variability?

NIPCC’s conclusion, drawn from its extensive review of the scientific evidence, is that any human global climate signal is so small as to be embedded within the background variability of the natural climate system and is not dangerous. At the same time, global temperature change is occurring, as it always naturally does. A phase of temperature stasis or cooling has succeeded the mild twentieth century warming. It is certain that similar natural climate changes will continue to occur.

In the face of such facts, the most prudent climate policy is to prepare for and adapt to dangerous climate events and changes regardless of their origin. Adaptive planning for future hazardous climate events and change should be tailored to provide responses to the known rates, magnitudes, and risks of natural change. Once in place, these same plans will provide an adequate response to any human-caused change that may or may not emerge.

Policymakers should resist pressure from lobby groups to silence scientists who question the authority of the IPCC to claim to speak for “climate science.” Climate Change Reconsidered II: Physical Science reveals a scientific community deeply uncertain about the reliability of the IPCC’s computer models, its postulates, and its interpretation of circumstantial evidence. This criticism doesn’t come from a “fringe” of the climate science community: It is stated plainly and repeated in thousands of articles in the peer-reviewed literature.

The distinguished British biologist Conrad Waddington wrote in 1941, “It is … important that scientists must be ready for their pet theories to turn out to be wrong. Science as a whole certainly cannot allow its judgment about facts to be distorted by ideas of what ought to be true, or what one may hope to be true (Waddington, 1941).”

This prescient statement merits careful examination by those who continue to assert the fashionable belief, in the face of strong empirical evidence to the contrary, that human CO2 emissions are going to cause dangerous global warming.


[i] Source: “Executive Summary,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).

[ii] Source: “Chapter 2. Forcings and Feedbacks,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).


[iii] Source: “Chapter 1. Global Climate Models and Their Limitations,” Climate Change Reconsidered II:

Physical Science (Chicago, IL: The Heartland Institute, 2013).


[iv] Source: “Chapter 4. Observations: Temperatures,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).


[v] Source: “Chapter 3. Solar Forcing of Climate,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).


[vi] Source: “Chapter 5. Observations: The Cryosphere,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).


[vii] Source: “Chapter 6. Observations: The Hydrosphere,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).


[viii] Source: “Chapter 7. Observations: Extreme Weather,” Climate Change Reconsidered II: Physical Science (Chicago, IL: The Heartland Institute, 2013).