Your Reading List

Extremely likely warming is human-caused, panel says

I have to start this article off with a bit of a correction. In the article I wrote a couple of weeks ago, I mentioned that the Northwest Passage was not open this year. What I should have said was that the Northwest Passage was not ice free this year. According to the National Snow and Ice Data Centre (NSIDC), for an area to be declared ice free it has to have less than 15 per cent of the water surface covered in ice. At no point in its data records did the Northwest Passage have all areas meet these criteria this year. So, while the Northwest Passage was not ice free this year, that doesn’t necessarily mean it wasn’t navigable, a fact that was quickly pointed out to us. The bulk cargo ship Nordic Orion (an ice-strengthened bulk carrier) successfully made the transit this year, making it the first such ship to do so.

Now on to the main topic for this issue, the latest release by the Intergovernmental Panel on Climate Change (IPCC). The first thing I want to point out about this report is that it’s intended to be a summary — if you can say that considering the total report is apparently over 3,000 pages long — of the research that has been done of the last five or so years on the state of the Earth’s climate. The report comes out in pieces over the next year, with the first piece being a short “Summary for Policy Makers” which was released in late September. It is put together by a large group of scientists and government officials from around the world and is meant to summarize the current state of knowledge on climate change. The scientists working on these reports are not paid for their IPCC work and they use or cite over 9,200 scientific papers, but do not present any original work of their own. Once the report was written it was reviewed by over 1,000 experts in 55 different countries before being reviewed by government representatives from 38 different nations. The Summary for Policy Makers, which was just released, had to go through a week-long review process and required approval of all 195 member nations of the IPCC. I guess what I am trying to point out is that this document is not something that is just quickly slapped together by a few people. The IPCC reports probably have the most detailed and elaborate review process of any scientific report.

The main question most people have about climate change and global warming is “How much has the planet actually warmed and what is causing it?” According to the IPCC, the Earth has warmed about 0.85 C over the last 130 years, with the majority of this warming (0.6 C) occurring since 1950. The report points out that since 1950, there have been no natural explanations for warming and in fact, it appears the Earth should have cooled slightly due to natural influences. The report also states that it is extremely likely (over 95 per cent) that the warming we are seeing is human caused.

The range of warming that is to be expected if carbon dioxide (CO2) levels double has changed slightly. The values range from a low of 1.5 C to a high of 4.5 C. Even if the lowest value occurs, that would still be almost a doubling of the warming we have seen so far. Current trends in CO2 indicate we’ll easily see double the CO2 levels well before the projections used in the IPCC report.


A lot of attention from skeptics lately has talked about the fact that the rate of warming over the last 10 to 15 years has slowed and the explanations for this from climate change scientists have been weak as they simply state it is natural climate variability. I think the best way to look at this is by examining the graphics I’ve included above, which show two ways to interpret the same climate data. I’ll let you decide which way you want to interpret it.

I also want to include a quote made on Dr. Jeff Masters’ blog at Weather Underground: “Physics demands that the massive amounts of heat-trapping carbon dioxide humans have dumped into the atmosphere must cause significant warming, but the chaotic complexity of the system is expected to obscure the magnitude of the long-term trend on time scales of a few years to a decade. The attention being to this latest ‘speed bump’ on the highway of global warming is a direct result of a well-funded PR effort by the fossil fuel industry. One has to look at the total warming of the atmosphere, oceans, land, and ice to judge the true progress of global warming, not just the surface temperature. There has been no slowdown in total global warming when we regard this entire system, as I argued in a post earlier this year. More than 90 per cent of the energy of global warming goes into the oceans, and the reason for the relative lack of surface warming this decade is that more heat than usual is being stored in the oceans. That heat will be released to the atmosphere at some point, removing the ‘speed bump.’”

I’m almost out of room for this week, but we’ll look at this report some more in upcoming issues.

About the author

Co-operator contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the U of W. He operates a computerized weather station near Birds Hill Park.



Stories from our other publications