As an additional note, I would be remiss not to note that the global average temperature at the Earth's surface has hardly increased at all. CO2 levels have continued to rise, but temperatures have not. No one knows why this is so, and anyone who claims to draw firm conclusions at this point in time is a liar and a cheat... we simply do not know. [...
I thought temperatures had been rising. [...
You are right! The belief that it hasn't warmed since 1998 is ranked #9 on the list of global warming and climate change myths!
"It hasn't been cooling since 1998. Even if we ignore long term trends and just look at the record-breakers, that wasn't the hottest year ever. Different reports show that, overall, 2005 was hotter than 1998. What's more, globally, the hottest 12-month period ever recorded was from June 2009 to May 2010.
Though humans love record-breakers, they don't, on their own, tell us a much about trends -- and it's trends that matter when monitoring Climate Change. Trends only appear by looking at all the data, globally, and taking into account other variables -- like the effects of the El Nino ocean current or sunspot activity -- not by cherry-picking single points."
TRANSCRIPT:
Global warming over the last 16 years
Mankind has continued to warm the planet through greenhouse gas emissions over the past 16 years. However, a persistent myth has emerged in the mainstream media challenging this fact. Let us examine what has been happening.
Here are observed global temperatures for the past 130 years from NASA. The last 35 years show a significant increase in global temperature. However the rate of warming is not uniform - there is a lot of variation from year to year.
Some of the variation comes from natural causes. Major volcanic eruptions inject small particles into the upper atmosphere, which trigger a strong cooling effect over a few years. Ocean cycles such as El Nino also affect temperature: El Nino years tend to be warmer and La Nina years cooler.
The longer term warming trend arises from greenhouse gas warming driven by human emissions.
Is there any evidence for a slow-down in greenhouse warming over the last 16 years?
In order to detect a change in the human contribution to climate change, we have to first separate out the natural contributions.
First, we remove the cooling effect of the volcanoes, along with the smaller effect of changes in solar activity.
Next we remove the pattern of warm and cool years caused by El Nino and La Nina.
What is left is the human contribution to climate change, plus some wiggles due to weather.
So is there any evidence of a change in the rate of human-caused warming over the last 16 years?
No. The human contribution over the last 16 years is the same as before. Human-caused greenhouse warming, while partially hidden by natural variations, has continued in line with projections. Unless greenhouse gas emissions are brought under control we will see faster warming in future.
For more information, visit sks.to/16years
"There's also a tendency for some people just to concentrate on air temperatures when there are other, more useful, indicators that can perhaps give us a better idea how rapidly the world is warming. Oceans for instance -- due to their immense size and heat storing capability (called 'thermal mass') -- tend to give a much more 'steady' indication of the warming that is happening. Here records show that the Earth has been warming at a steady rate before and since 1998 and there's no signs of it slowing any time soon."
Land, atmosphere, and ice heating (red), 0-700 meter ocean heat content (OHC) increase (light blue), 700-2,000 meter OHC increase (dark blue). From
Nuccitelli et al. (2012).
Last updated on 10 January 2013/..."
Sources:
What has global warming done since 1998?
Arguments from Global Warming Skeptics and what the science really says
