Global warming stopped in 1998 (apparently)?

Question

It has been stated in this section that global warming stopped in 1998, is there any evidence to support this claim?

Thanks everyone who answered. One or two points to add.

No-one managed to include a link to source claiming GW stopped in 1998.

1934 is the hottest year only in the continental US, 2005 is the hottest year globally (unless you include part years in which case it's 2007).

The NASA data was not proven incorrect, it was recalibrated to bring it in line with more recent temp records (something that happens frequently). The average temp change across the dataset was less than one thousandth of a degree per year.

The NASA data is just one of many datasets used to create a global record (GHCN), with the revised figures added to GHCN nothing changed.

1880 is not the first year of data, it's the first year of the GISTemp dataset, 1659 is the first year of instrumentally recorded data, 542 million BC is the start of reconstructed data.

1971 is the last 'negative year' in the global 5 year mean.

Talking of 5 year means, the 10 hottest years on record are 2007, 2006, 2005, 2003, 2004, 2002, 2001, 2000, 1999, 1998. Using a 10 year mean then every year since 1973 has been progressively hotter.

I have absolutely nothinjg against skeptics, they're an essential part of the GW debate and when they're comments are accurate they make a valuable contribution, it's just a shame that there's so many inaccuracies.

Good answers from Dana, Enraged Parrot, Rando and Keith but can only choose one best answer.

Answer 1

There is no evidence to support this claim, but the problem is that the explanation of why it is incorrect is subtle. Understanding climate physics is all about understanding subtlety and complexity. Most laymen, especially those with a predisposition to doubt that mankind's activities are affecting the radiative transfer of the Earth's atmosphere, want a simple explanation, they want linearity and simple correlations. Unfortunately, climate science and all of the physics and chemistry that go into it are not like that. They do not yield to simple analysis typical of freshmen college level understanding and reasoning.

As you are aware, 1998 was a year with a huge El Nino cycle, and El Nino correlates with higher than normal global mean temperatures. The large increase in the 1998 global mean temperature was an outlier in a rather steady upward trend and the decrease in global mean temperature from 1998 onward is more likely due to the onset of steady La Nina conditions than a global cooling trend from a change in radiative forcing. That this is the most reasonable explanation for what was going on with global temperatures at the close of the 20th century is not something that is tractable in a 3-sentence answer.

I like this quote from a paper from Park and Mann, published in 2000 in Earth Interactions (citation below):

"It is germane to ask if this study can shed any light on whether the 20th century increase in global temperature is anthropogenic or the result of natural variability. Natural variability cannot be rejected out of hand as a contributing factor, because periods of exceptional ENSO variability are also suspected to correlate with large pre-industrial climate variations (Quinn and Neal, 1992). Exceptional variability can also be found in both long ENSO-proxy records (Dunbar et al., 1994) and in low-resolution coupled ocean-atmosphere model simulations (Knutson et al., 1997). On the other hand, we have identified behavior in the instrumental temperature record that motivates a scenario of how hemispheric temperatures might increase irregularly in response to a steady increase in radiative forcing. This scenario suggests that if atmosphere and ocean reequilibrate after the post-1975 interval of secular atmospheric warming, global temperatures might level off for a few decades, similar to the 1940–1975 interval. Any such respite would likely be followed, however, by another interval of rapid warming. One can imagine that such a pause in the warming trend would complicate the incontrovertable detection of anthropogenic climate forcing and, moreover, any international governmental efforts to reduce greenhouse gas emissions. The irregularity of warming during the 20th century has been cited as a reason to doubt a causal connection with more monotonically increasing greenhouse gas concentrations (e.g., Balling, 1992). Further study is needed to determine how ENSO and its large-scale patterns of influence might change character in response to changing boundary conditions associated with greenhouse warming or other external forcing of climate and what timescales of response might be expected for such changes."

From:

Jeffrey Park and Michael E. Mann, "Interannual Temperature Events and Shifts in Global Temperature: A “Multiwavelet” Correlation Approach", Earth Interactions, Volume 4, Issue 1 (January 2000), pp 1-36

Answer 2

Only if you don't know math. The fact that 1998 was, until 2005, the hottest year on record led a number of right-wing, non-scientist loudmouths to proclaim that global warming stopped in 1998.

The fact is that the proper way to determine whether global warming has stopped is to use regression, and the regression slope for world temperature during the period 1998-2006 is positive using both the NASA/GISS dataset (+1.9°C per century) and the Hadley dataset (+0.8°C per century).

Answer 3

The only "evidence" is the fact that 1998 was the hottest (or I guess now second-hottest behind 2005) year on record. The logic is if it hasn't gotten hotter than 1998, then clearly the planet is no longer warming!

Like most attempts to comprehend global warming via layman's logic, it doesn't work.

*edited to add* I can't believe the deniers are still claiming that 1934 was the hottest year on record. If you can't even understand the difference between the lower 48 United States and the planet Earth, then how can you hope to understand that the fact that 1998 was the hottest year (until 2005) doesn't mean that global warming has stopped?

Please go back and get some edumacation, folks.

Answer 4

1934 is now officially the hottest year on record in the continental United States, by a ridiculously small fraction of a degree, but 1998 remains the hottest year on record on a global scale.
Climate is a slippery thing to define, but year-over-year averages are not a good gauge of climate change, since there's considerable variation from one year to the next. Remember, the scale of climate change over the past century is only 1 or 2 degrees. That's why climatologists talk about rolling 10-year averages rather than taking individual years in isolation.

Answer 5

"The only "evidence" is the fact that 1998 was the hottest (or I guess now second-hottest behind 2005) year on record. The logic is if it hasn't gotten hotter than 1998, then clearly the planet is no longer warming!"

this is intellectually dishonest.

you, being a scientist, KNOW that NASA's data was PROVEN INCORRECT!

the revised data shows the year1934 being the hottest year on record.

http://data.giss.nasa.gov/gistemp/graphs/Fig.D.txt

why are you omitting the facts to promote your beliefs?

why do you wish to confuse the uninformed?

is that what science is all about?
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1998 is not the last year the warming stopped.

i'd like to also point out during 1929 to 1948 was a period of global warming, as shown in the 5 year mean.

the last negative year in the 5 year mean is 1984.

it still isn't conclusive if we broke that '29-'48 streak yet.
if we do, we STILL don't know if this is abnormal.

1880 is the first year of data. so we have 126 years of data. less than 1/2 the time the United States has existed. some people have almost lived this long.

so we are going to judge (INTELLIGENTLY) what is normal based on this literal blink of time?

how can we REALLY know, factually, what is normal and abnormal.

Answer 6

I'm one of those 'laymen' who don't have all the scientific statistics and what not, but the more ignorant responses seem to be coming from the anti-GW side. Of course, there are exceptions but I thought the misinformed statement that 1934 was the hottest year was already cleared up.

Answer 7

Well, the reasoning behind the statement, as close as I was able to tell from a skeptic's explanation to me, is summed up in this fantastic little graph I made. I'm crappy at doing spreadsheets, so no fair laughing.

http://s86.photobucket.com/albums/k111/EnragedPirate/?action=view¤t=tempgraph.png

The yellow line represents what is supposed to be a "cooling trend," somehow.

Answer 8

It hasn't been as hot as it was in 1998. The Earth is starting to cool down, right?

Answer 9

I will let you know exactly when global warming ended, and it will change your life. I just need a little more time.

I wan't to party with you bud....

Answer 10

NASA corrected their mistake. The new hottest year is 1934.