How does current global warming compare to previous warming events?

Question

There have been times in the past when the planet has warmed up and cooled down. How does the rate of historical warming and cooling compare to the current rate by which temperatures are changing?

Please feel free to use any global temperature record you like and compare the current warming/cooling to whatever time in history you like.

RON C: Thanks, good answer. When comparing one year to any other year the mean values are used (it eliminates anomalies caused by events such as El Nino). When using a mean value for the years you mentioned the figures are similar (can't recall them off the top of my head) but it's necessary to take into account the respective natural and human components. For example, although the world is warming at the moment there is an underlying cooling trend - so whilst the apparent rise in temps is double that of the early 20th C the real rise is greater. Also, about one third of the rise in temps in the early 20th C was anthropogenic, when all factors are taken into account the current rate of warming is about double and the human component is about 6 times as much.

Answer 1

Using the HadCRUT3 data like Ron C, the most recent warming is about 0.022 deg C per year.

http://www.cru.uea.ac.uk/cru/info/warming/

Comparing this to the warming from 1910-1940 isn't really relevant, because human greenhouse gas emissions played a role in that warming, too.

Instead I'll compare it to a warming event in which humans played no role - from the trough at the last ice age to when it approached the current stable temperature range.

http://upload.wikimedia.org/wikipedia/commons/7/77/Vostok_420ky_4curves_insolation.jpg

During that period, the planet warmed approximately 8 deg C in about 8,000 years, or 0.001 deg C per year.

Thus I conclude that the current warming rate is over 20 times greater than when the planet naturally exits an ice age.

Answer 2

no even close ,the climatic conditions and changes were enormous

the Earth was formed after a cosmic collision and 2 planets merged to become this one ,the moon was a fragment that broke off during the collision
and for millions of year this planet was a hot red rock
the life was only in the seas,
nothing could survive on the land for the first few billion years
at first 40 odd % more carbon dioxide

with earlier stuff like jelly fish,and much later giant under water scorpions
a few 100 million years later
things began to crawl on the land when the first kind of plants and fungi started


few 100 million years later.
it was total vegetation with 60% more oxygen .with ferny trees,we could never have lived in that

then before the dinosaurs ,it was 40% hotter

a few 100 million years later
it became a practically a desert plant ,
again,much hotter than we could survive in

temperature changes were enormous and fatal to the bulk of the life at any of these given times
there were times that the whole planet had volcanic eruptions

a few 100 million years later.
we had hard winters and hard summers and vegetation began again,still would have killed us all

a few 100 million years later

began the dinosaurs and this slowly started to become a jungle planet again with the first trees like the bristle cone pine.

it was not until millions of years after that,that the climate became suitable for us to breathe for the first time

check history or animal planet there is a documentary called ,
walking with monsters -life before the dinosaurs (2005)

fascinating stuff on the origin of life and the huge differences in climatic global conditions ,any of these changes would have killed all of us if we could uberhaubt have lived then (and we could not )with temperature changes of hundreds of degrees,and huge differences in oxygen and carbon levels

so in fact we never had it so easy,
but it would only take another cosmic event to change all that

which is what the Mayas ,Egyptians ,Olmecs and a few others ,were on about,when all the planets are lined up as they are getting now ,and their astrology was superior than ours is today ,

they must have had inside information.

Answer 3

Using the anomaly data from CRU.

In 1976, the anomaly was -0.254 rising rapidly to 0.42 in 2006 = difference of 0.674 in 30 years or 0.022 per year.

In 1910, the anomaly was -0.548 rising rapidly to 0.018 in 1940 = difference of 0.566 in 30 years or 0.019 per year.

While this comparison shows the current warming to be slightly greater than the warming early in the 20th century, the difference is not statistically significant. It is a difference of 3 thousandths of a degree per year.

In addition, the problems with the surface temp record are such that the earlier warming is greatly underestimated. Do you really believe it is warmer today than during the "dust bowl" years of the 1930s and early 1940s? I do not.

EDIT - Note to Dana. Most global warming alarmists admit that CO2 played almost no role in the warming in the early 20th century. The world's population in 1910 was about 20% of today's population and the number of trains, planes and automobiles was maybe 5% of today's levels. The amount of warming from CO2 would not be measurable during this period. It was not until after WW2, that CO2 emissions really picked up. Trevor said he thinks the warming from 1910-1940 was mainly from solar variation.
http://uk.answers.yahoo.com/question/index?qid=20071119213113AATqYFk

I just came across a video of Prof Bob Carter discussing previous warm periods going back much earlier. He shows that the current rate of warming has happened many times before.
http://youtube.com/watch?v=FOLkze-9GcI

In the next video segment, Carter says it is common for temps to change 2.5C per century.
http://youtube.com/watch?v=vN06JSi-SW8&feature=related

Answer 4

Johnny, it is not now "hotter than ever." In fact, past global maximums have all been 3-4 degrees Celsius higher than current temperatures. Not surprisingly, this is the current "best estimate" for the maximum in the current warming trend.

Answer 5

Trevor above me provides a ton of bullshit. The whole idea of CO2 causing warming is based on an assumption of high climate sensitivity. This is not proven and actually has evidence of not being true.

Answer 6

A nice pretty graph is at the site reference below. Also you will notice that CO2 concentrations follow temperatures. This is from the Vostok ice core data and is publicly available.

Answer 7

its more hotter than ever! we need to work now and do many projects to stop this global warming. it more rates higher than ever abot 20 percent or something.