What mechanisms have been proposed for the supposed halt in global warming?

Question

It is sometimes claimed in the press and online that global warming stopped at some recent point, 1998 or so.

The mainstream theory, that CO₂ emissions from human activity were the primary driver of 20th century global warming, holds that warming since 1998 is merely obscured by ENSO cycles and other short-term noise. The mainstream theory predicts that warming has not stopped, and will continue for some time.

What alternative theories for the cause of 20th century global warming have been suggested, that are consistent with the warming observed last century, and consistent with the claim that warming stopped around 1998? Do these alternative theories predict that warming will remain stopped? (For example, is the urban heat island effect believed to have increased through 1998 and is now declining?)

Anonymous · Accepted Answer

Global temps have been rising slightly for 3 decades with 10 of the warmest days on record appearing in the last 12 years, yet the deniers say the earth has been cooling for 15 years. The deniers say it is the Sun which has been in a cooling cycle. They claim it is a worldwide hoax designed to line Al Gores pockets But they are the only ones who even bring up Al Gore. The rest of us really don't give him a thought. .They say it is warm now because it was warm a millennium ago. They can't back any of this up with peer reviewed science.

If you want to see the failings of their arguments        http://skepticalscience.com

antarcticice · Answer

Urban heat island is a denier fantasy like many others they offer, it has no valid science to support it, it is a tiny effect in terms of global surface area.
As for 1998 and a cool down, I really don't get how anyone could be fooled by such nonsense, 1998 was a clear spike in temperature, above the years before it or after it (till 2005) AGW didn't cause that spike a record El Nino did, it is marked as the strongest of the last 100 years it lifted both 1997 & 1998. 1997 only disappeared from the record a few years ago. As a guide to how much we are 'cooling' ask yourself this 2008 was a cooler year thanks to a quite strong La Nina coinciding with a continuing PDO event, yet even with denier claims of new ice ages and other silliness 2008 equaled 1997 in temperature
http://www.ncdc.noaa.gov/sotc/global/2009/13#gtemp
The above is the NOAA listing of the ten warmest years (circa 2009)  this repeated again in 2011, and again deniers made claims about the end of warming yet 2011 was actually warmer than 2008
http://www.ncdc.noaa.gov/sotc/global/2009/13#gtemp
What you have is a cycling event ENSO (AKA El Nino/La Nina) when it spikes we have a warmer year when it is in La Nina phase we have a cooler year this explains 2011 & 2008 just as El Nino explain 1998 beyond that there is no cooling trend, the background trend is warming and that has not stopped.
compare the 1980s to the 1990s and the 2000s for yourself
http://www1.ncdc.noaa.gov/pub/data/cmb/hazards/2011/12/enso-global-temp-anomalies.png
can any denier honestly say the 2000s are cooler than the 1990s the 2 coolest years that denier like to play up (2008,2011) are warmer than any year before 1998 in the 130 year span of the modern record.
http://climate.nasa.gov/keyIndicators/index.cfm#globalTemp

As far as dampers on AGW the PDO is certainly one, the current event started around 2006 and may last a few more years or a decade, the PDO is unpredictable, but it will end and when it does you will see 1998 fall like a stone through the list of warmest years, and with it, will go denier fantasies about ice ages that are going to start next Tuesday.

Anonymous · Answer

Global warming has not stopped but, because of natural cycles, such as ENSO, the Sunspot cycle and volcanoes, it does not proceed at a uniform rate. The warming appeared to be rapid between 1992 and 1998 because of the recovery from Mt. Pinatubo and the 1998 el Nino. More recently, the Sun entered into a deep minimum. This slowed down global warming, but it did not stop it. 2008, the coldest year in the solar minimum was it the top twelve years in the instrumental record, even though soar foricng would have made it one of the coolest years since 1880. The reason why 2008 was in the top rather than in the bottom record years was because of carbon dioxide; there is no other known reason.
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.txt

The urban heat island effect is not declining. Urban areas continue to grow. Do note that denialists love to claim that the urban heat island effect is a major driver of the trends, not because the urban heat island effect is causing a significant change in the energy balsnce, but that is causing erroneous temperature readings. But rural areas are warming just as much as cities.
http://www.skepticalscience.com/urban-heat-island-effect-intermediate.htm

Denialists also love to look at short term effects rather than long term trends, when looking at temperatures, sea level and arctic ice coverage.
http://www.skepticalscience.com/graphics/SkepticsvRealists.gif

garrytoo · Answer

Global warming didn't stop in 1998, it's continuing on at an accelerated rate, with no hope left for stopping it, in the not so far future our coast lines will be alot farther into our countries because of rising water levels worldwide. Eventually all of us living in the northern hemisphere will have to move alot farther south, because of the rapid cooling of the earth will throw us into another ice age.

Jonathan · Answer

It's simply not a factual statement. So there is no need to address it.

For a simple lesson or two about things like that, see below.

Trending News

What mechanisms have been proposed for the supposed halt in global warming?

5 Answers