The modern man, his lifestyles and the products he produces and uses, is responsible for a lot of the increase in the stock of greenhouse gas emissions in the atmosphere which has driven global warming.
There has been an explosive growth of greenhouse gas emissions in the past few decades. The situation doesn’t seem to be improving despite more awareness that the climate crisis threatens life as we know it.
These are some reflections upon reading the latest report of the UN Inter-governmental Panel on Climate Change (IPCC), launched recently in Berlin.
It was the third IPCC report in its Fifth Assessment series. The first, on physical science aspects, was completed last September. The second, on adaptation, was adopted in late March in Yokohama.
This third report was quite contentious, as it dealt with mitigation, including such sensitive topics as how much to reduce emissions, how it can be done, and how much this would cost.
The meetings were intense as participants grappled with how best to portray the complexities of so many aspects to one of the world’s most pressing problems; and the atmosphere was tense as governments fought on ways to explain who and what were to blame for the crisis, and how to share the burden of reducing emissions in the future.
The facts in the 33-page Summary for Policy Makers (SPM) were stark indeed, including that:
–Half of all carbon dioxide emissions from 1750 to 2010 occurred in the last 40 years.
Cumulative carbon dioxide from fossil fuel combustion, cement production and flaring by 1970 (since 1750) reached 420 giga tonnes but this had tripled to 1,300 giga tonnes in 2010, showing the tremendous increase in the past 40 years;–Greenhouse gas annual emission was about 39 giga tonnes of carbon dioxide equivalent in 2000, but this grew by about 1 giga tonne per year to reach a high of 49 giga tonnes by 2010;
–Without additional mitigation action to reduce emissions, the concentration of greenhouse gases in the atmosphere, driven by growth in population and economic activities, is expected to jump from 430 parts per million (ppm) of carbon dioxide equivalent in 2011 to 450 ppm by 2030 and 750-1,300 ppm by 2100;
–This growth in emissions and concentration of greenhouse gases is projected to raise the global mean surface temperature in 2100 by 3.7 to 4.8 degrees centigrade above the pre-industrial levels.
(The present temperature is about 0.8 degree above pre-industrial levels; a rise by over two degrees is considered damaging while a four-degree rise would be catastrophic).
–To keep global warming below two degrees relative to pre-industrial levels, the concentration of greenhouse gases should not exceed 450 ppm of CO2 equivalent.
To attain this concentration (and not higher), this implies global greenhouse gas emissions in 2050 should be 40-70 per cent below the 2010 level, and near zero or below in 2100.
–Governments have to do more in mitigation action than what they have pledged so far (at Cancun in 2010) as those pledges, if implemented, would only keep global temperature rise below three degrees relative to pre-industrial levels, which would have disastrous effects.
The SPM is a summary report, negotiated among governments and scientists, that is meant to tell policy makers in a few pages what an “underlying report” details in more than a thousand pages.
While the scientists are responsible for the contents of the underlying report, they together with the governments are jointly responsible for the SPM, which is why the IPCC is seen as such a powerful body.
Actions to be taken
There is buy-in by the governments for a report that is science-based but tempered (or diluted, depending on how one looks at it) by the views of a wide range of governments with diverse and often different views.
One of the useful things in the report is that it also summarises in a few pages the actions that can be taken to reduce emissions.
It provides the advantages of taking actions in various sectors but also points out the disadvantages, barriers and costs of doing so.
The summary report has, however, little to say that is new or useful on how the governments can cooperate and act to cut emissions. What kinds of agreements and understandings can they consider that are fair and effective? What key issues do they need to resolve and why is it hard to get the solutions?
Those are difficult questions and answering them properly was perhaps too much a task for the scientists or not in their mandate. All in all, the IPCC has produced a valuable set of reports that should be seen as a state of the art on where we know we stand vis-à-vis the climate situation, and the difficult choices in tackling the crisis overall.
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