Global Temperatures Global Troposphere Temperatures click here For full size []]
Providing Insight
Into Climate Change
Climate Change Science Essay

Compiled by Ken Gregory,
Calgary, Alberta, Canada

Revised: November 3, 2021   (Revision history)

Table of Contents

          The Science in Summary
          Greenhouse Gas Effect
          Climate Is Always Changing
          Temperature Leads CO2 Changes
          Sun Activity Correlates with Temperature
          Sun and Cosmic Rays
          Milankovitch Cycles
          Heating of the Troposphere
          Stratospheric Cooling
          CO2 Versus the Sun Warming Theories          
          IPCC and Model Projections
          Computer Models Fail
          Water Vapour Feedback 
          Cloud Feedback
          Climate Sensitivity
          Ocean Oscillations
          The IPCC Hockey Stick
          Urban Heat Island Effects
          Falsified Historical CO2 Measurements
          No Consensus
          Effects of Warming
              Sea Level Rise
              Severe Weather
              Warming Is Good for Your Health
              Agriculture and Climate Change
              Warming Effects on Animals
         CO2 Increases Plant and Forest Growth
         Kyoto Protocol - Misallocation of Funds
         Warming on Other Planets
         An Inconvenient Truth
         Warnings of Global Cooling

A goal of the Friends of Science Society is to educate the public about climate science and the scientific merits of the hypothesis of human induced global warming. The science of climate change is complex. Unfortunately, politics and the media has affected the science. Climate research institutions know that they must present scary climate forecasts to receive continued funding - no crisis means no funding. The media presents stories of climate disaster to sell their products. Scientific research that suggests climate change is mostly natural does not receive much if any media coverage. These factors have caused the general public to be seriously misled on climate issues resulting in wasteful expenditures of billions of dollars in an ineffective attempt to control climate. This document gives an overview of climate change issues as determined by a comprehensive review of the state of climate science.

Global Lower Troposphere Temperatures and Model Mean

The graph above shows the temperature changes of the lower troposphere from the surface up to about 8 km as determined by the University of Alabama in Huntsville (UAH) satellite data. The best fit line from January 1979 to October 2021 indicates a trend of 0.135 Celsius/decade.  The sharp temperature spikes in 1998, 2010 and 2016 are El Nino events. Surface temperature data is contaminated by the effects of urban development. The Sun's activity, which was increasing through most of the 20th century, has recently become quiet. The magnetic flux from the Sun reached a peak in 1991. The high magnetic flux reduces cloud cover and causes warming. Since then the Sun has become quiet, however it continues to cause warming for about a decade after its peak intensity due to the huge heat capacity of the oceans. The data are obtained from microwave sounding units (MSUs) on the National Oceanic and Atmospheric Administration's satellites, which relate the intensity or brightness of microwaves emitted by oxygen molecules in the atmosphere to temperature. The MSU data set represent the temperatures of a layer of the atmosphere that extends from the surface to approximately 8 kilometres (5 miles) above the surface. The dark red line is the 5-yr centered average of climate models' lower troposphere. The model trend is 199% of the measurements.


The Science in Summary

The history of the Earth tells us that the climate is always changing; from warm periods when the dinosaurs flourished, to the many ice ages when glaciers covered much of the land. Climate has always changed due to natural cycles without any help from people.

The United Nations Intergovernmental Panel on Climate Change (IPCC) is a political organization promoting a theory that recent minor temperature increases may be caused largely by man-made carbon dioxide (CO2) emissions. CO2 is an infrared gas, and increasing concentrations can potentially increase the average global temperature as the gas absorbs long-wave radiation from the Earth and emits the absorbed energy. However, the warming ability of CO2 is limited because much of the absorption spectrum is near saturated. When CO2 concentrations were ten times greater than today the Earth was in the grips of one of the coldest ice ages. The climate system is dominated by strong negative feedbacks from clouds and water vapour which offsets the warming effects of CO2 emissions.

The history of climate and CO2 concentration shows that temperature changes precede CO2 changes and can not be a major driver of climate. Temperature changes over different time scales have been well correlated to solar cycles, cosmic ray flux and cloud cover. Recent research shows that cosmic rays act as a catalyst to create low clouds, which cool the planet. When the Sun is more active, the solar wind repels the cosmic rays, reducing low cloud cover allowing the Sun to warm the planet.

Computer model results presented in the IPCC Fifth Assessment Report predict that global warming will cause a distinctive temperature profile in the atmosphere of enhanced warming rate in the upper atmosphere at 8 to 12 km altitude over the tropics. The predicted temperature profile is the result of an expected increase in water vapour in the upper atmosphere which would amplify a CO2 induced warming three fold. The computer models are programmed to forecast a constant water vapor relative humidity with increasing CO2 resulting in a large water vapor feedback. Actual temperature data shows no such enhanced warming profile. Therefore, the comparison of observed data to computer models proves that no such water vapour induced warming amplification exists, so CO2 is not the main climate driver. In atmosphere layers near 8 km, the modelled temperature trend from 1980 is 200 to 400% higher than observed. Weather balloon data shows that specific humidity has fallen 9% since 1960 in the upper troposphere (400 mbar pressure level) where the models predict the greatest feedback. Adding CO2 to the atmosphere may reduce upper atmosphere water vapour, the most important greenhouse gas, resulting in only a small increase of the greenhouse effect.

An analysis of satellite data shows that clouds cause a strong negative feedback on temperature, but climate models assume that clouds cause a positive feedback. Modelers assumed that all cloud changes are caused by temperature changes which results in them inferring a positive feedback. But changing cloud cover can also cause temperature changes. Scientists can now separate these two effects. The correct analysis shows that clouds cause a strong negative feedback, so if temperatures increase, cloud cover increases, reflecting solar energy back to space and greatly reducing the warming effect of CO2 emissions.

Several planets and moons have warmed recently along with the Earth, confirming a natural sun caused warming trend. Over longer time periods, as the solar system moves in and out of the galactic arms the cosmic ray flux changes, causing ice ages and warm ages. A comparison of temperature and solar activity proxy data suggests that solar effects can explain at least 75% of the surface warming during the last 100 years.

CO2 is plant food and the increase in the CO2 concentration may have increased the global food production by 15% since 1950 resulting in huge benefits for people. For Canada, any CO2 warming effect would also benefit us by reducing our space heating costs and making a more pleasant climate.

The IPCC predicts that global average temperatures will increase by 0.17 to 0.38 oC per decade to the end of the century depending on the rate of CO2 growth in the atmosphere and other assumptions. The projections assume that no action is taken to limit CO2 emissions. However, these predictions are unrealistic because they falsely assume that the recent temperature changes are driven solely by CO2 and that the Sun has little effect on climate. A recent study of past climate change used by the IPCC has been shown to be wrong due to the use of a faulty algorithm, and the inappropriate selection of data.

The land temperature record is contaminated by the urban heat island effect. Fully correcting the land temperature record would reduce the warming trend from 1980 to 2002 by half. The IPCC historical CO2 record may be incorrect due to inappropriate adjustments to the ice core data, and ignoring direct historical CO2 measurements. The IPCC selects and adjusts data to conform to its CO2 warming hypothesis and ignores alternative climate theories. This is the wrong way to do science. Many scientists strongly disagree with the IPCC conclusions.

The sea level data shows no increase in the recent rate of sea level rise, and no such increase is expected over the next hundred years. There has been no detected increase in severe storms and there is no reason to expect an increase in the number or intensity of hurricanes resulting from any warming assumed to be from human caused CO2 emissions.

Any increase in temperatures due to human caused CO2 emissions will likely be beneficial to human health. The CO2 fertilization effect will increase the rate of forest growth and CO2 induced crop yield increases will reduce the pressures to cut down forests for farmland expansion. This will greatly benefit animals by slowing habitat destruction.

The benefits of CO2 emissions greatly exceed any likely harmful effects. Several authorities who have studied solar cycles have warned that the Earth may soon enter a cooling phase as the Sun is expected to become less active. The atmosphere may warm because of human activity, but if it does, the expected change is unlikely to be more than 0.8 C, and probably less, in the next 100 years.


The Greenhouse Effect

This graphic from Trenberth et al 2009 here, shows the exchange of energy among Space, the Sun, the atmosphere and the Earth.

Global Energy Flows

Greenhouse gases are primarily water vapour, carbon dioxide and ozone. Greenhouse gases are mostly transparent to incoming solar radiation, but absorb outgoing long wavelength radiation. The absorbed energy is then transferred to cooler molecules or radiated at longer wavelengths than the energy previously absorbed. This process makes the Earth warmer than it otherwise would be without the greenhouse gases (but with the atmosphere and clouds) by about 33 degrees Celsius.

Water vapour and clouds together account for over 70% of the total current greenhouse effect. However, in terms of changes to the greenhouse effect due to human activities, water vapour is generally considered a feedback and not a forcing agent. Computer simulations show the a uniform 1.8% change in water vapour has the same effect on outgoing longwave radiation as a 10% change in CO2 concentration. (See the water vapour feedback section for further information.)

More greenhouse gases reduce the transparency of the atmosphere to longwave radiation from the surface.

See here for a discussion of CO2 versus water's contribution to the greenhouse effect.

Radiation transmitted

The top panel of the graph above shows the absorption spectral intensity of the greenhouse gases. Most of the short wave length solar radiation in the visible part of the spectrum is transmitted to the surface. Most of the upward thermal long wave radiation from the surface is absorbed except in the atmospheric window indicated by the blue region. About 16% of the long wave radiation is transmitted directly to space and the rest is absorbed by greenhouse gases. The middle panel shows the total absorption bands by wavelength of downward solar radiation and upward thermal radiation. The gray shading at 100 percent indicates that the energy is fully absorbed at that wavelength. The lower panel shows the absorption of the major greenhouse gases. Comparing the CO2 and H2O absorption spectra shows that much of the CO2 spectrum overlaps with that of water. Parts of the CO2 spectrum are already fully saturated. Adding more CO2 will result in ever diminishing effects as more of the available wavelengths become saturated. The temperature response to adding CO2 to the atmosphere depends on the amount of positive and negative feedbacks from water vapour, clouds and other sources. The temperature effect of increasing CO2 concentration is approximately logarithmic. This means if doubling the CO2 concentration from 300 ppm to 600 ppm, a 300 ppm increase, causes the temperature to rise by 1 oC, it would take another 600 ppm increase to add a further 1 oC temperature gain. Methane has an absorption band (at 8 micrometres) that largely overlaps with water vapour, so an increase in methane has little effect on temperature.

Modtran upward irradiance

The above diagram shows the upward radiation spectrum from the top of the atmosphere at 20 km with 300 ppm CO2 and 600 CO2 as calculated by the Modtran radiative code. (Note that the horizontal axis of this diagram shows wavenumber, or number of wavelengths per cm, which is the reciprocal of the wavelength in micrometers used in the previous diagram.)  This model calculated radiation is very similar to what is actually measured by satellites from space. The green curve shows the emissions spectrum with 300 ppm CO2 in the atmosphere and the blue curve shows the spectrum with 600 ppm CO2 with the same surface temperature and water vapour profile. The model shows that doubling the CO2 concentration changes the spectrum only at the edges of the main CO2 absorption band, at 600 and 740 cm-1.  The resulting forcing of 3.39 W/m2 would cause the surface temperatures to increase if not offset by negative feedbacks.

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