Archive for May, 2008

Comparing Zonal Trends in the 20th Century

May 23, 2008

During the 20th century, we’ve seen three distinct global temperature trends:

1) A warming period from 1910 to 1942,

2) A cooling period from 1942 to 1978, and

3) A warming period from 1978 to the present.

The graph below is of global temperature (as collected by the GISS) from 1880.

The warming in the early 20th century is largely seen as natural.  CO2 levels in the atmosphere were not increasing nearly enough for anyone to claim that it caused the extent of warming recorded.  Similarly, the mid-century cooling can’t have its roots in CO2 output, and instead was likely caused by increased particulate pollution and decreased solar activity.  The warming seen since 1978 is what is so contentious.   The purpose of this post is to compare zonal trends during the two warming trends.

Below are two graphs that show zonal trends in temperature during the perid 1910-1942.

Below are two more graphs, representing zonal trends over the period 1978-2007.

As you can see the zonal temperature signal for both periods are nearly the same.  This is important because anthropogenic global warming promoters use the high lattitude warming as evidence for the effect of increased CO2 levels on temperature.  Yet, this same pattern of warming, best demonstrated by the zonal mean vs lattitude charts, was observed during a completely natural period of warming.  There is one notable difference between the trends observed during the two periods, though.  Warming seen in Northern Asia and Europe during the modern warming did not occur during the period of natural warming.  As I see it, there are a few explanations: 1) This Siberian warming has been caused by increased CO2 levels in the atmosphere. 2) The magnitude of the modern warming has been somewhatlarger, which might have caused a warming signal that the smaller, natural warming did not exhibit. 3)  The warming periods are both natural, though they were not caused by the same climate shift.  For example, warming during the first half of the century may have been caused by increases in total solar irradiance, while this modern warming may have its origins in oceanic circulation.  This would result in different regional trends.

So, there are two points to be made about this zonal trend analysis.

1) Arctic warming may be natural.  It has occured before with equal intensity, and thus Arctic warming is not evidence for a CO2 forcing.

2) The two periods of warming are not entirely the same.  The modern Siberian warming that some attribute to rising CO2 levels did not occur during the natural warming.  When I saw Harvard astrophysicist Willie Soon, Ph.D. speak at the International Conference on Climate Change, he attributed this warming to changes in regional oceanic currents.  I am sure that there are other possible explanations, and I may post something about it in the future.

Advertisements

Part 1 of Data Compilation: UAH Atmospheric Data

May 21, 2008

Here’s UAH atmospheric data as part of the project I have started to compile all atmospheric and galactic data relevant the the global warming debate.  I extracted it and graphed it from here: http://vortex.nsstc.uah.edu/public/msu/.  I have also calculated temperature trends for each graph.  I have taken Lower Tropospheric, Middle Tropospheric, and Lower Stratospheric temperature trends and presented them as global, NH, SH, Tropics, Ocean, Land, Arctic, & Antarctic trends.

There are a few things I’d like to point out.

1) The lower stratospheric data shows a strong cooling trend.  Yet, there has been no cooling in the past decade, and it seems that the only cooling that occurs is directly after major volcanic eruptions, as if the aerosols spewed by the volcanoes remains temporarily in the atmosphere.  Maybe this is just a coincidence, though it would be valuable to find out.

2) Lower stratospheric tropics data varies much more widely than NH or SH lower stratospheric data.

3) Mid-tropospheric temperatures have remained relatively stable.

4) Lower tropospheric temperatures are relatively stable, aside from a strong warming signal in the high lattitudes of the NH, especially the Arctic.

5)  Mid-tropospheric temperatures in the Arctic seem to possibly be cyclical with a period of around 20 years.  If it is cyclical, it may be interesting to look into any connection with the 22 year solar Hale (?) cycle.

Trend Data

May 19, 2008

I did some work with excel to create a graph that would show the slope of a linear regression for each year through the present.  Essentially, the data point at a certain year Y shows the trend in temperature from year Y to the present.  This “trend” is not derived from just taking the endpoints and finding the change in temperature, but instead by finding the slope using all data points in the given time interval. Below is a graph representing what I have been describing.  As the year approaches the present, there is less data to work with, so the trends become increasingly eratic and of large magnitude.

Below is a graph that extends only through 2003, so it is easier to see the trends before 2003.

As you can see, it is safe to say that the temperature trend is upward from 1980-1998 to the present.  In 1998, the Earth underwent a massive El Nino, raising global temperatures and creating approximately an even trend in temperature during the past decade.  We can also say that the temperature trend has been even since 2001, and downward since 2002, 2003, 2004, etc.  This is important because of claims of recent of “global cooling” or that global warming has stopped.  Certainly, global warming has stopped since 2001, making 7 years without warming.  We can take it a step farther and say that “global cooling” has occured since 2002, making it 6 years of cooling. 

So the next question is, how statistically significant is a 7 year stable temperature trend and a 6 year cooling trend.  I chose UAH (University of Alabama at Huntsville) data for two reasons: 1) It is sattelite based, and thus not effected by urbanization bias. 2)  It covers the period of 1980 to the present, which exhibits warming that some claim has been caused by CO2 emissions.  Therefore, to answer my question about statistical significance, I need to go into the full 28 years of data to see if the 7 year stable temperature and 6 year cooling trend exist.  I am guessing that they do.  Below is graph of actual UAH temperature.

As you can see, it is very likely that a 6 year cooling trend (remember, using linear regression not endpoints) exists elsewhere in the data.  In fact, it appears that an 8 year cooling trend exists from 1980-1988.  Therefore, recent claims about “global cooling” and that “global warming has stopped” may be statistically insignificant, unless the case can be made the climate as a whole is showing signs of stablization, which may very well be the case.  Based upon changes in oceanic circulation (the PDO recently going negative) and projected weak solar intensity over the next two solar cycles, this current trend of “global cooling” may continue and become statistically signifiant.

Data! And lots of it.

May 13, 2008

A theory is nothing without evidence to back it up.  Similarly, evidence is nothing without a theory to explain it.  In this post, I am laying out all climatic and galactic data needed to evaluate the various theories about the cause of global warming.  There is significant debate about what specific data sets properly measure the phenomenon listed below, and this makes things very difficult.  This post merely contains the data needed, and in following posts, I will go from data subject to data subject, assessing what data sets are most appropriate for measuring the phenomenon.  In the end, I would like to compile correct data for all climate and galactic phenomenon relevant to the global warming debate from 1880 to the present.  Having this sort of database would be extremely helpful, and it would limit the debate to theory. 

 

*Note that italicized statements are to emphasize theoretical speculation for temperature response

 

Changes in Climate

Temperature

Surface Temperature

                -Arctic

                -Northern Hemisphere

                -Tropics

                -Southern Hemisphere

                -Antarctica

                -Any other notable regional trends?

Atmospheric Temperature

                -Troposphere

                                -Arctic

                                -N. Hemisphere

                                -Tropics

                                -S. Hemisphere

                                -Antarctica

                -Stratosphere

                                -Lower Stratosphere

                                -Upper Stratosphere

                -Mesosphere

                -Thermosphere

                -Exosphere

Oceanic Temperature

                -Upper

                -Middle

                -Lower

 

Precipitation

-Arctic

-Northern Hemisphere

-Tropics

-Southern Hemisphere

-Antarctica

-Any other notable regional trends?

 

Water Vapor Content

-Global Trend

-Any specific regional trends?

 

Cloud Cover

-Upper Atmosphere

-Middle Atmosphere

-Lower Atmosphere

 

Heat Budget

-Ocean Heat Content

-Atmospheric Heat Content

-Other Heat Reservoirs

 

Radiation

-Incoming shortwave

-Outgoing longwave

 

Possible Explanations for Above Changes in Climate

Greenhouse Gas Levels

-CO2

-Methane

-Other gases

-Theoretical temperature response is logarithmic, ignoring atmospheric expansion

 

Solar Data

-TSI­

-Sunspot number

-Cycle Length

-Solar Wind Intensity

-UV Radiation

-Energetic Particle flux

-Linear temperature response or integrated temperature response?

 

Other Galactic Data

-Galactic Cosmic Radiation levels

-Linear temperature response? 

-Or asymptotic cloud formation (and thus temperature) response?

-Lunar-Terrestrial Gravitational Interplay

                -Linear temperature response?

 

Oceanic Oscillations

-Pacific Decadal Oscillation

-Atlantic Multi decadal Oscillation

-ENSO Cycle

-Other Cycles

-Sum of all Cycles

 

Global Albedo

-Volcanic controbution

-Anthropogenic aerosol contribution

Posts from the Old Site

May 8, 2008

Huge Cooling over the Past Year

The Beginning of the End

The NEW Theory of Climate Change

—I’ve recently moved away from this theory.  It may be a peice of the puzzle, but climate’s too complex to be dominated by one mechanism.

New Paper Shatters the “Consensus” Myth

Beware the History Channel

Criticism of the “Hockey Stick” #1: Data Mining & A “New” Statistical Method

Relevant Events and Cycles in Paleoclimate

Summary of My Position