Changes

===The Modern Warm Period===

===The Modern Warm Period===

The average [[Earth]] surface air temperature has risen about 1° F since 1970.  

The average [[Earth]] surface air temperature has risen about 1° F since 1970.<ref>Hansen's group at the Goddard Institute wrote, "Global warming is now 0.6&nbsp;°C [1.0&nbsp;°F] in the past three decades and 0.8&nbsp;°C [1.4&nbsp;°F] in the past century." Hansen, J. E. and Reudy, R. et al. (January 12, 2006). [http://data.giss.nasa.gov/gistemp/2005/ "GISS Surface Temperature Analysis"].  NASA/Goddard Institute for Space Studies.  Retrieved on September 26, 2014.</ref> Studies have ruled out the possibility that errors in the measurements and sampling significantly affect the temperature trends detected over the past century. This accounts for spatial errors in the sampling and thus also incorporates errors associated with the urban-heating effect. According to Karl et al. (1994) ''"Results imply that the errors associated with century-scale trends of temperature are probably an order of magnitude smaller than the observed global warming of nearly 0.5°C per 100 years since the late nineteenth century"'' <ref>Karl, Thomas R., Knight, Richard W. et al. (July 1994).  [http://adsabs.harvard.edu/abs/1994JCli....7.1144K "Global and hemispheric temperature trends: uncertainties related to inadequate spatial sampling" [abstract&#93;].  ''Journal of Climate'', vol. 7, iss. 7, pp. 1144-1168.  Abstract retrieved from The SAO/NASA Astrophysics Data System on September 26, 2014.</ref>

<ref>Hansen's group at the Goddard Institute wrote, "Global warming is now 0.6&nbsp;°C [1.0&nbsp;°F] in the past three decades and 0.8&nbsp;°C [1.4&nbsp;°F] in the past century." Hansen, J. E. and Reudy, R. et al. (January 12, 2006). [http://data.giss.nasa.gov/gistemp/2005/ "GISS Surface Temperature Analysis"].  NASA/Goddard Institute for Space Studies.  Retrieved on September 26, 2014.</ref> Studies have ruled out the possibility that errors in the measurements and sampling significantly affect the temperature trends detected over the past century. This accounts for spatial errors in the sampling and thus also incorporates errors associated with the urban-heating effect. According to Karl et al. (1994) ''"Results imply that the errors associated with century-scale trends of temperature are probably an order of magnitude smaller than the observed global warming of nearly 0.5°C per 100 years since the late nineteenth century"'' <ref>Karl, Thomas R., Knight, Richard W. et al. (July 1994).  [http://adsabs.harvard.edu/abs/1994JCli....7.1144K "Global and hemispheric temperature trends: uncertainties related to inadequate spatial sampling" [abstract&#93;].  ''Journal of Climate'', vol. 7, iss. 7, pp. 1144-1168.  Abstract retrieved from The SAO/NASA Astrophysics Data System on September 26, 2014.</ref>

According to temperature reconstruction made within an [[Old Earth]] paradigm, there have been many cycles of naturally-caused global warming and cooling over many millions of years (see [[climate cycles]]). Some scientists, including [[Richard Lindzen]] of [[MIT]], [[Sallie Baliunas]] of [[Harvard]] and [[Fred Singer]] (independent), say that the recent warming could be part of another natural cycle or random fluctuations in the atmosphere. However, many scientists also think that human activities were most likely the cause of the the planet's recent warming.

According to temperature reconstruction made within an [[Old Earth]] paradigm, there have been many cycles of naturally-caused global warming and cooling over many millions of years (see [[climate cycles]]). Some scientists, including [[Richard Lindzen]] of [[MIT]], [[Sallie Baliunas]] of [[Harvard]] and [[Fred Singer]] (independent), say that the recent warming could be part of another natural cycle or random fluctuations in the atmosphere. However, many scientists also think that human activities were most likely the cause of the the planet's recent warming.

It should be noted, however, that computer simulated climate models are often tweaked so they agree with the historical temperature record. There is no way to completely simulate all of the Earth's climate with a computer program.

It should be noted, however, that computer simulated climate models are often tweaked so they agree with the historical temperature record. There is no way to completely simulate all of the Earth's climate with a computer program.

After a major set of temperature readings was found to be an incompatable mix of older and recent data (in the Climategate II scandal) in 2010, Judith Curry, chair of the School of Earth and Atmospheric Science at America’s Georgia Tech university examined new data causing her to state (as quoted by MailOnline):<ref name="Rose"/>

After a major set of temperature readings was found to be an incompatible mix of older and recent data (in the Climategate II scandal) in 2010, Judith Curry, chair of the School of Earth and Atmospheric Science at America’s Georgia Tech university examined new data causing her to state (as quoted by MailOnline):<ref name="Rose"/>

<blockquote>'Natural variability  [the impact of factors such as long-term temperature cycles in the oceans and the output of the sun] has been shown over the past two decades to have a magnitude that dominates the greenhouse warming effect.</blockquote>  

<blockquote>'Natural variability  [the impact of factors such as long-term temperature cycles in the oceans and the output of the sun] has been shown over the past two decades to have a magnitude that dominates the greenhouse warming effect.</blockquote>  

<blockquote>Professor Phil Jones, director of the Climate Research Unit at the University of East Anglia, who found himself at the centre of the ‘Climategate’ scandal over leaked emails three years ago, would not normally be expected to agree with her....  Prof Jones also admitted that the climate models were imperfect: ‘We don’t fully understand how to input things like changes in the oceans, and because we don’t fully understand it you could say that natural variability is now working to suppress the warming. We don’t know what natural variability is doing.’</blockquote>

<blockquote>Professor Phil Jones, director of the Climate Research Unit at the University of East Anglia, who found himself at the centre of the ‘Climategate’ scandal over leaked emails three years ago, would not normally be expected to agree with her....  Prof Jones also admitted that the climate models were imperfect: ‘We don’t fully understand how to input things like changes in the oceans, and because we don’t fully understand it you could say that natural variability is now working to suppress the warming. We don’t know what natural variability is doing.’</blockquote>

===Sunspots===

===Sunspots===