South Carolina's Wettest Summer

This past summer was cool and wet for Columbia and this was the topic of a previous post.  It turns out that Columbia was not alone.  In fact some areas had much more rain than Columbia.  The mountains of South Carolina saw record rainfall for the summer with an average of over 40 inches.  On August 6^th over 5 inches of rain fell in the Upstate resulting in one drowning death in Pickens County.

Summer rainfall averaged for the mountains of South Carolina (division 1) since 1895.  2013 was the wettest on record.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.

The wettest areas were in the Upstate, Pee Dee, north coastal, and central divisions of South Carolina.  These divisions saw record summer rainfall while all other divisions were at least in the top 10 wettest.

A ranking of summer rainfall for South Carolina since 1895.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.

A ranking of summer rainfall for South Carolina since 1895 with other states in the U.S.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.

Just Another Number?

Numbers have meaning only in context.  A temperature of 98.6 degrees F is normal body temperature, but only in context of the mean.  This is not normal for every person.  The S&P 500 crossing 1600 is meaningless unless it is in context of what the market is doing.  Is it going up or down?  How far has it gone from previous levels?  Only then does the number have meaning.

A milestone was reached recently, Thursday, May 9^th, at the Mauna Loa Observatory in Hawaii.  Levels of carbon dioxide reached 400 parts per million (ppm) for the first time in human existence.  Daily measurements are made at the observatory of the gases that lead to atmospheric change.  One of the main gases monitored is carbon dioxide (CO2).  Levels of 400.03 and 400.08 ppm were measured independently by the National Oceanic & Atmospheric Administration (NOAA) and Scripps Oceanographic Institute respectively.

Mauna Loa Observatory in Hawaii.  Click on the image for a larger version.  Image Credit: NOAA/ESRL.

This was a daily mean that was measured for the first time.  Hourly measurements exceeded this number quite a few times since mid-April.  The monthly mean of CO2 will likely peak this month, at a level of about 399 ppm, and then fall until October.  It is likely to pass the 400 ppm in the spring of next year.  The yearly mean will not likely cross this level until 2015 or 2016.

When Weather Becomes Climate

Note: It has been a busy three weeks which included a week of much needed vacation.  Much has happened in the interim.  I am working on a number of posts which will be rolled out in May.

Meanwhile, many people often confuse weather with climate.  You have heard the refrains like it is so cold, how could the earth be warming?  Or how can we be in a drought when we’re having a flood?  Just when does weather become climate?  Good question!  Meteorologists at the European Space Agency have produced an answer to that question.

The following video is about 12 minutes long, but it is well produced and worth the time to view it.  They have a wealth of information with which to determine climate change and it is interesting comparing weather in the early 1800’s to weather today.  I hope you enjoy this production.

Click here: When Weather Becomes Climate

It's All About Chemistry

In 1827 the French mathematician and scientist, Jean-Baptiste Joseph Fourier postulated that something in the atmosphere was helping keep the earth warmer than it might otherwise.  He is generally credited with discovering the greenhouse effect even though he did not coin the phrase.  However, his work set the stage for later developments in the nineteenth century.

It was the British scientist John Tyndall who demonstrated the absorption of infrared radiation from different gases in 1861.  His work found that nearly all of the greenhouse effect was due to just a few trace gases like water vapor and carbon dioxide (CO2).  This was a startling discovery, because it had huge implications for Earth’s climate.

The Swedish chemist Svante Arrhenius was the first to actually detail how a doubling of carbon dioxide would change the global temperature with the publication of his work in 1896.  His work eventually led to the Nobel Prize in Chemistry in 1903.  He is recognized with beginning modern climate science.

The discovery of global warming is a fascinating story.  I highly recommend the book by Spencer Weart by the name The Discovery of Global Warming.  If you are interested in the scientific papers, it is available in the collection called the The Warming Papers edited by David Archer and Raymond Pierrehumbert.

Note that the foundation of climate science occurred over a century ago.  It is also noteworthy that the trace gases were recognized for their ability to influence Earth’s climate as far back as the nineteenth century.

Fast forward to today.  The burning of fossil fuels has fueled (pardon the pun) the world economic growth.  China and the U.S. are the two largest emitters of CO2.  In the latest accounting the global growth in emissions continues.

How do we know that the increases in CO2 come from burning fossil fuels?

Extreme Heat: The Odds Are Increasing

A number of people have been asking me during this exceptional heat wave if it was being caused by global warming.  My response has been that “global warming doesn’t cause the heat wave; it causes the heat wave to be hotter.”  Privately I had been telling people that we would likely break the all-time record high temperature in Columbia in the next 20 years.  That was two years before it happened.

The fact that so many record high temperatures are being broken is no surprise.  A 2009 study published in the Geophysical Research Letters showed that daily record-high temperatures were outpacing daily record lows by a 2:1 ratio in the first decade of this century.  If the climate were not warming the ratio would be 1:1.  The study showed that on a business as usual scenario the ratio would expand to 20:1 by 2050 and 50:1 by 2100.

The ratio of high to low temperature records from the 2009 study listed above.  Click on the graphic for a high-definition view of the graph.  Image Credit: Climate Central.

However, this year the ratio has expanded to 7:1 for the nation since the beginning of the year.  Almost 8,000 high temperature records have been set in just the past month.  Some of these records recently have been all-time record highs breaking records from the Dust Bowl Era.  Keep in mind that there have been two record heat events already this year.  The first was the record warm spell in March and now the exceptional heat wave this past month.

The ratio of high to low temperature records for June and the first half of 2012.  Click on the graphic for a larger view.  Image Credit: Climate Central.

Drought Worsens in South Carolina

Droughts are hard to define.  Meteorological droughts are prolonged periods with less than average precipitation, but the prolonged period is nebulous.  How many weeks or months must go by before a drought is declared?  Again this depends on how much precipitation has occurred.  Obviously if no precipitation occurs then it doesn't take long to enter a drought.  Defining when a drought started can also be difficult.  Thus, you often do not know that you are in a drought until it gets serious.

Remember December 2009?  The precipitation total for that month in Columbia was 9.31 inches, almost three times the normal value.  It was a record wet December.  In addition the four month of September through December totaled 25.96 inches which was a record for that four month period.  What happened?  A strong El Nino was in progress and most of the rain that year came in just that four months.

Click on image for the larger version.

In the 28 months since that time there have only been four months of above normal rainfall.  So in retrospect we have been in a period of drought since January 2010.  The rainfall deficit has been enormous during this time.  The deficit in Columbia has reached 25.57 inches in the past 28 months.  However, it is much worse along the Savannah River where Augusta has amassed a deficit of 38.71 inches in the same time period.  Thus the western part of South Carolina is in worse shape than the northeastern part of the state and this is reflected in the USDA Drought Monitor.

Record March for the U.S.

March 2010 in Columbia, SC.  Image Credit: Climate Central.

Those of us in central South Carolina already know that this past March was the warmest on record.  I outlined the records in a previous post.  The graphic to the left covers the period since 1948.  The year of 1974 was the warmest during this time.  However, the records do extend back to 1888 and 1945 was the previous record.

The record warmth was not confined to central South Carolina.  Much of the central and eastern U.S. were part of this record breaking event.  March is usually a transitional month with weather systems progressing across the country producing a wide variety of weather conditions.

Image Credit: NOAA/NCDC.

However, this year was a year characterized by a ridge of high pressure in the East and a trough of low pressure in the West.  The chart to the left shows the mean 500 mb (about 18,000 feet in the atmosphere) heights and the height anomalies for the month.  The blue areas show where the heights were lower than normal and are related to the persistent troughs of low pressure.  The red areas correspond to above normal heights and are related to the areas of higher pressure.  This caused the jet stream to frequently dip far to the south along the West coast and then retreat north into Canada.

A Record March for Columbia

If you thought it was warm in March, you were right.  Much of the U.S. east of the Rockies saw record or near record warmth for the first month of spring.  This follows the 4^th warmest winter for the U.S. as a whole.  More information will be released from the National Climatic Data Center next week.

However, we do have the information for Columbia.  It was a record March for the city and not by just a small amount.  The average temperature for the month was 65.4 degrees beating the previous record of 64.7 set in 1945.  This was almost 10 degrees (9.8) above normal for the month.

Top 5 Warmest

Mean Temperature                       Year                         Temperature

2012	65.4
1945	64.7
1921	63.9
1907	62.5
1974	61.7

Collapse of Mayan Civilization Related to Drought

As a youngster growing up in Florida I often read about the Indian civilizations in Central America.  The two most talked about in history classes were the Aztec and Maya.  The Mayan civilization was considered one of the most advanced civilizations of its time.  They made significant contributions to math and astronomy.

Mayan Temple

The Mayan civilization ranged over what is now southern Mexico, Guatemala, and parts of Honduras.  Their cities were large with ceremonial pyramids.  They developed quite a culture with fine sculptures, paintings, and ceramics.

Yet, the civilization collapsed between 800-950 B.C.  There have been a number of theories put forth to explain the collapse.  These include, drought, disease, and sociopolitical conflicts.  None of these can be ruled out, but it appears that whatever the ultimate cause was climate change stands out.

A paper has just been published in Science by British and Mexican scientists.  Here are excerpts from the press release from the University of Southampton in the UK: