I wrote this during lunch, and since then things have moved on, but after all that effort, I'm darned if I'm going to edit it all. SO there will be some repetition of what other have said, but so far Tom has added nothing that makes much difference.
OK, Tom. Time to fisk [*cracks knuckles*]
whoa, what short memories you have! Lets track back a touch, the world was warming for about two decades and we were warned of “Global Warming” Then came a general cooling trend the past 10 or 11 years and the mantra was changed to “Climate Change” not because of a single outlier year but due to a trend of cooling.
Firstly, the underlying warming trend was not just for the 80s and 90s. It goes back about 100 years, but has been more marked since the 1960s. Satellite data only goes back to when we had enough coverage, so to the 1970s, but the trend is verified there.
Secondly, we have not really had a general cooling over the past decade. The actual trend for the past 10-11 years has been fairly flat, not really a cooling as much as a slowdown in the warming. It could be that this is the end of a warming period, or it could be a pause, but it is not yet a sign of a cooling trend.
Thirdly, the term Climate Change has been used for much longer than you suggest. Temperature is only one factor in climate, there are also humidity/precipitation and prevailing winds or currents, and it is likely that a major change in one will have an effect on the others, so researching climate is more than just about whether we are warmer. If this phrase is so new, how come the IPCC (International Panel on Climate Change) was established with that name in 1988, about
ten years before your claimed cooling trend would have started, let alone have been noticed?
Suddenly the cooling never happened?
Yes, the average is still higher than many past decades but it is in normal ranges
The cooling is not as much of a fact as you seem to think it is, as mentioned above (and below). The last decade was not ‘normal’, it was the warmest decade that we have ever recorded, and certainly warmer than any decade from the previous century, indeed as far back as we can tell from historical records. I would love to know how you would include that in a definition of normal.
If CO2 is continuing to increase and the theory states that the earth will warm then why has it not continued to escalate?
Well, I can think of two candidates. There are known solar cycles that have an effect. Look up the sun-spot cycle. It runs over an 11 year period. At the height of the cycle (the last peak was around 2001-2002) we see warming. At the troughs we see cooling (the last trough was in 2007-8). So we would expect that if all were equal, the early part of the last decade would be warmer than the latter part. It’s actually about the same (and the variance much less than between this decade and the previous one) Additionally, the intensity of the peak activity has been shown to be a factor in global temperature. The Medieval maximum is believed to have been a period of higher peak sun-spot activity. The period afterward certainly coincides with the Maunder Minimum of the 1600s, when sunspots became much rarer for several decades. The last peak was slightly lower than in recent cycles, which in theory should have made this decade slightly cooler than normal.
Another factor is El Nino/La Nina. In La Nina years, the global average tends to be lower. In an El Nino year, it tends to be higher. In the last decade we have had only one short El Nino period, but far more La Nina.
So, that’s two possible reasons for you that may explain why the underlying increase has been observed to slow down. There is also the reality of random variation in datasets based on a huge number of factors and inputs, such as the temperature record or a stock market Index. A short period of downticks or flat activity in the Dow after a long term period of rises does not necessarily mean that the underlying trend is no longer upwards. It might be related to a particular sector (or even a single company if it is large enough) having a problem. The only way to be sure is to see what happens afterwards.
Now it could be that El Nino/La Nina cycle changes are caused by, rather than a cause of climatic changes. And it could be that the sunspot cycles are contributing more than we think to the current trend. So, as I have always maintained, we need more research and more data to look at as many contributory factors as possible. Certainly looking at one decade in isolation is not actually that useful. The issue is that the current scientific position suggests that if we wait too long it could too late to do anything, and so it would appear prudent to take precautionary measures in the meantime, even if you are unconvinced by the science.
It’s not a one year outlier (even then, it would still make no sense) but rather a decade or more of cooler weather than a decade ago.
Tom, if you don’t understand the effect of outliers in statistical analysis, then I suppose this must be confusing for you. But if there’s an unusually warm year that brings up the longer term average, then removing it will clearly have some effect on the average. The lower the number of years you average over, the more likely that an outlier will perturb the results.
Still, I want to be clear about what you are saying here though. Are you saying that the average temperature for 2000-2009 was lower than it was for 1990-1999? Everything I have seen suggests that this is not the case, even if you include 1998. According to NASA, 2008 was the coolest year of the past decade, and yet was warmer than each of 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 and 1999. Several years in the past decade have been about as warm (or for 2005, warmer) than 1998. So it is
impossible for the nineties to have been warmer than the noughties on that basis.
Even if you meant to compare 2000-2009 with 1995-2004, a simple paring of the uncommon years (because the common years of 2000-2004 will cancel each other out) shows that 2005 was higher than 1995, 2006 was higher than 1996, 2007 was higher than 1997 and 2009 was higher than 1999. The difference in just one of those (2009 and 1999) is greater than the amount that 1998 was warmer than 2008. So again, the average for 2000-2009 is higher than for 1995-2004.
Now, before you start, the NASA data is not the same data as the in famous Hadley CRU data. NASA uses the GISS (Goddard Institute for Space Sciences) data instead. Even though the CRU data has not actually been found to be incorrect, I have deliberately avoided using it because I am aware that the scandal of a year or so ago means that it is tainted and you would challenge any use of it. If you have an issue with the GISS data, please explain what it is before deciding you can ignore it or make vague claims about cherry picking. If you have alternative sources, that show a different trend, then by all means let us know.
Until then, your assertion that there has been a cooling would appear to be contradicted by the facts. Repetition of a falsehood does not make it a truth. Repetition of a proven falsehood is called lying.