In the science of climatology how many years determines a cooling or warming trend?

Question

In the science of climatology how many years determines a cooling or warming trend?

Answer 1

Ok Gee whiz...   you know jack abt wx or climate.  

Climatology is an everyday event.

Take a look at the 5pm climatology data at the airports.

That weather is recorded and entered into archives.  From that data we can calculate temperatures, dew points, winds and pressure for any time of the day of any season.

There are so many variables that is sounds so lame to hear people act as if they understand weather.   Yes,  global warming is cult like.   Very irrational people opining on very complex sciences.

Answer 2

Climatologists usually aren't interested in anything shorter than 30 years. Otherwise, it's just weather.

Answer 3

It depends on who you're working for and what data you are seeking.  If we use the chart that Bob provided, which specifically talks about surface temperature, it shows a warming trend, for surface temperatures.  And the chart is for a 100 plus year period in 5 year interval measurements on the chart.  If you go to the U.S. Historical Climatology Network website, you can use any amount fo time period you want to get the result you want.  Play with it for awhile and watch the trend go up and down depending on region and time span you use.  If you use the temperature measurements from West Point for the entirety of the time they have been measuring temperature, there is no discernable change.  So, depending on the type of climatologist you are, paleoclimatologist for example, and the information you are looking for, the time period will be different.

Answer 4

Do it like the UN climate change committee did...

Step 1) Decide what result you want to show.

Step 2) Find a set of data ( it doesn't matter how small or incomplete it is ) which shows your desired result.

Step 3) Hide all data for the subject outside your chosen range.

Step 4) Tell everybody we're all going to die and you have proof.

Answer 5

THEIR WONT BE ANY COOLING TREND, BECAUSE GLOBAL WARMING IS SPECIFICALLY AN INTENT TO DELETE ALL LIFE ON EARTH FOR A NEW SPECIE.

Answer 6

About five years.

You an see it clearly in the graph below.  The annual average data is very "noisy" due to weather.  Taking the five year average removes most of the noise, and lets the trend show through.

http://data.giss.nasa.gov/gistemp/2007/

Answer 7

Warming/cooling trends vary a lot, as short as a few years to maybe a century.  Depends mostly on sun spots. The more sun spots, the more it changes.  At the moment there are almost no sunspots so it's cooling.

Answer 8

"The trend is your friend until it ends, my friend"

Old investment adage.

Seems appropriate here for some reason.

Answer 9

American Meteorological Society definition of climate change:

Any systematic change in the long-term statistics of climate elements (such as temperature, pressure, or winds) sustained over several decades or longer.