Part 3: A Gathering Storm
define abrupt climate change as a transition of the climate system
into a different state (of temperature, rainfall and other aspects)
on a time scale that is faster than the responsible force (mechanistic);
change of the climate system that is faster than the adaptation
time of social and/or ecosystems (impacts).
Recognizing the imperative need for understanding such an occurrence better, the National Oceanic and Atmospheric Association has been expanding and intensifying their efforts to bring the
best minds and the latest technology together to attempt to increase the curve, if you will in understanding out climate.
As I mentioned earlier in this piece, the data is there for you to see, read and interpret for yourself.
One site, in particular, is NOAA's
Climate Monitoring Group. Another is
NOAA's division of Paleoclimatology.
Their professionalism in their attempt to understand the intricacies of climate and climate change on this Planet Earth and their openness to discuss that work is excellent.
At these sites, you can find climate data for each month of the year in easy-to-understand language, and, most importantly, you can see how that
particular month ranks among other similar months for which records were maintained.
The most consistent comment by many scientists attempting the "Don't worry, be happy" approach to our climate says that, while change does
occur and is currently taking place, it does so over a long period. However, IF these changes were just beginning, then we are way ahead of the curve
to respond and prepare, but what if the changes began decades ago? Can we continue to put on a happy face? Let's take a look at the data, as
recorded and stored at the NOAA site and look for catch phrases or sentences that, in and of themselves, may not seem significant, but when added up, paint a less then rosy picture of where we might be on this
"Change Continuum." In short, even using the most conservative time line for abrupt climate change, might we already be well into that change?
You can't possibly foretell the future
without first understanding the past.
Often, the best way to understand the future is to understand the past a little better. Science is doing exactly that now. In the field of Climatology, the
sub discipline that delved into the past is Paleoclimatology. What exactly is the past showing us?
According to NOAA's
Climate Monitoring Group:
Paleoclimate evidence from ice cores, tree rings and other natural recorders reveals that large changes in climate such as in temperature and precipitation have happened in the past.
The changes have occurred over decades to centuries, sometimes affecting small regions and sometimes entire hemispheres. The changes are massive compared to anything we have experienced since people have been
keeping records of climate.
Until recently, many scientists studying changes and variations in the climate thought that the climate system was slow to change, and that it took many
thousands if not millions of years for ice ages and other major events to occur. Scientists are just beginning to formulate and test hypotheses regarding the causes of abrupt climate change, but only a handful
of attempts have been made to model abrupt change using computer models.
Furthermore, there is reason for concern. What concerns NOAA is to them, the ultimate question, "What if these abrupt climate changes were to occur
in the future? Would ecosystems be affected? How would humans adapt?
These questions motivate a vigorous research effort to understand the changes of the past, and eventually to predict future abrupt climate change
." They say that abrupt climate change can occur within decades (end of the Younger Dryas) or centuries. Both, according to NOAA are considered
abrupt events because they are fast in relation to their cause.
NOAA's Paleoclimatology program is attempting to view and understand abrupt climate change from two perspectives. The first is a Mechanistic
approach that they define as a "Transition of the climate system into a different state (of temperature, rainfall, and other aspects) on a time scale
that is faster than the responsible forcing." The other is an Impacts based approach, which is defined as "Change of the climate system that is faster
then the adaptation time of social and/or ecosystems."
By bring the science of Paleoclimatology to bear; they are discovering some astonishing things. "One remarkable aspect of the paleoclimate
record is that it reveals rapid changes in climate at a much larger magnitude than anything we have experienced in the past few centuries."
One of the best-studied examples of abrupt change, according to NOAA, occurred as the Earth's climate was changing from a cold glacial to a warmer interglacial state. They have found:
During a brief period lasting about a century, temperatures in most of the Northern Hemisphere rapidly returned to near glacial conditions, stayed
there for over 1,000 years in a time called the Younger Dryas (named after a small Arctic flower,) then about 11,500 years ago quickly warmed again.
In some places, the abrupt changes may have been as large as 10*C, and may have occurred over a decade.
According to NOAA scientists, the impact today would be devastating and therefore, more than ever, "there is a pressing need to develop an improved
understanding and ability to predict abrupt climate change events. Indeed, this is the goal of several national and international scientific initiatives." In
addition, they say, "If scientifically possible, society needs to be able to predict such abrupt changes before they happen in the future in order to anticipate and mitigate the impacts of such changes."
While the preciseness of the technology has rapidly advanced, NOAA admits that, "The study of rapid or abrupt change still is in its infancy, and
while new data are published every month, the paleo record is still frustratingly incomplete."
As abrupt change is being refined, scientists continue to pose hypotheses regarding mechanisms, but only a handful of these mechanisms have been tested using climate models.
"Even for one of the best known abrupt change events, the Younger Dryas about 11,000 years ago, neither the global extent of temperature or precipitation change nor the accompanying changes in ocean circulation
and atmospheric trace gases are well known.
The next decade is sure to bring many new developments on this topic." Therefore, what do we know for certain? NOAA says:
At this point, we know that abrupt climate change is a reality. It has happened before and will happen again. How and why it happened in the past are still open
questions, as are how, why, and when it might happen in the future. The information found in natural archives of climate and environmental change such as ice cores,
lake and ocean sediments, tree rings, and other proxies can be of profound benefit to society in understanding and predicting future climate change.
To keep track of the latest developments in the field of Paleoclimatology, please visit
NOAA's division of Paleoclimatology.
A look at the record; and often, it's more than meets the eye.
We often hear that term in regards to a particular statistic. This month or that month was a record-breaking month when it came to a particular
weather element. Yet, it is critical to understand and analyze, not only what record was broken when compared to the previous record holder, but also
each record that was broken previously. Can establishing a list of records also indicate the pace of change?
Our first stop in attempting to see if we can determine a pattern is
NOAA's National Climate Data center, billed as the world's largest archive of climate
To illustrate this process of reading all the material to get the most precise picture possible, we'll take a look at weather data dating back to 1997 and
forward. Again, all the NOAA information is open and readily available for anyone to read.
According to the National Oceanic and Atmospheric Administration's
National Climatic Data Center in Asheville, NC, 1997 was the warmest year
of the 20th century, based on land and ocean surface temperature data. Led by the Center's Senior Scientist, Tom Karl, the team analyzed temperatures from around the globe during the years 1900 to 1997, and
back to 1880 for land areas. They found that "The record breaking warm conditions of 1997 continue the pattern of very warm global temperatures.
Nine of the past eleven years have been the warmest on record."
Even when there isn't a "record breaker" — pay attention to the overall picture. For example, NOAA's data indicated that, while land temperatures
in 1997 did not break the previous record set in 1990 (pay note to this), it was one of the five warmest years since 1880. It is perhaps very important to note that again, according to NOAA data, "Including 1997, the top ten
warmest years over the land have all occurred since 1981, and the warmest five years all since 1990." (Emphasis the author)
In addition, NOAA's data indicated that in 1997:
Ocean temperatures ... also averaged three quarters of a degree F (0.42 degrees C) above normal, which makes it the warmest year on record, exceeding the previous
warm years of 1987 and 1995. The warm El Nino event contributed to the record warmth of the oceans this year.
With 1997 in the record books, what happened in '98? That year saw more of the same. NOAA records indicate:
Global temperatures in 1998 were the warmest in the past 119 years, since reliable instrument records began. The previous record was set in 1997. This was the
20th consecutive year with an annual global mean surface temperature that exceeded the long term average.
A persistent El Niño in the first half of the year and
the unprecedented warmth of the Indian Ocean contributed to this record warm year.
Did evidence show that a trend was being established, or were 1997 and 1998 just abnormalities? According to NOAA, 1999 meant more of the same:
The Global mean (Land and Ocean combined) temperature for 1999 was the 5th warmest on record since 1880. Globally, the departure from the long term average
(1880 1998) was 0.41 degrees C (0.74F).
While the temperature was rising, so was the instance of natural disasters. NOAA, in their "year in review" tells us that:
In the Atlantic, another above average hurricane season, produced a 5 year period with the greatest number of tropical systems on record.
In the United States, over 200 tornadoes were observed in January, nearly 14 times the average number. In May, the U.S. experienced the second
greatest number of tornadoes on record, following 1998's record year. Although annual totals show a long-term increase since the 1950s.