Climate change

September 29, 2008

Ongoing rise in global carbon emissions and the lazy audience

Filed under: Carbon Pollution Reduction Scheme — Barry Brook @ 12:16 pm

The Global Carbon Project just released their annual report (’Carbon Budget 2007‘), which makes for rather depressing reading, at least if you were hoping for a turn-around any time soon in global carbon emissions. The media release associated with the report is packed with good information, and so I’ll reproduce it at the end of this blog post. There have also been some news reports on this in the Australian and international media in which I am quoted, such as here, here and here.

My comments on the report, made to AusSMC, are as follows:

The carbon emissions growth story coming out of the latest Global Carbon Project analyses isn’t getting any brighter. At the average rate of CO2 accumulation in the atmosphere over the last few years, we’ll reach a concentration of 450 parts per million by about the year 2040. And that’s an optimistic outlook under a business-as-usual economic scenario, if carbon ‘sinks’ in the ocean miraculously cease their decline in effectiveness, and industrial emissions growth somehow stagnates at the current output. A more realistic projection, accounting for further decline in carbon sinks and ramping up of industrial activity, suggests 2030 is a plausible timeline. But whatever the specific date, 450ppm CO2 commits us to >2 degrees C global warming and all the disastrous consequences this sets in train.

Of particular concern is that emissions from deforestation (mostly the burning of rain forest) in our nearest tropical neighbour region, Southeast Asia, continue to skyrocket. Not only is this damaging to this area’s rich biodiversity (because habitat is degraded and fragmented), but it also has a huge impact on the region’s carbon budget. Yet Southeast Asia, like Australia is particularly susceptible to the impacts of climate change from sea level rise and changes in rainfall patterns. Emissions from Southeast Asian forest loss now exceed those of Latin America or Africa – truly the global ‘hotspot’ of CO2 from deforestation. Australia’s regional role in abatement has never been clearer.

Each year that Australia’s industrial emissions and Southeast Asia’s forestry emissions continues to grow, our chances of avoiding the worst consequences of climate change diminish. Are we willing to continue to act like a lazy audience in a movie theatre, watching passively as a disaster film plays out in slow motion, in which we are the real-life actors? Who is going to ask the projectionist to turn off the reel before we get to the disturbing climax and the end credits start to roll?

This report is timely in the sense that it is a good lead in to another blog post I plan to make within the next few days, which will try to clarify the confusion around whether we are currently at atmospheric concentrations of 455 or 380 ppm CO2-equivalent. The answer is very much that… it depends…

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Carbon Budget 2007 Key Facts

(I also suggest you grab the PDF of their PowerPoint presentation, which has some excellent visuals)

[ppm = parts per million, 1 Pg = petagram (1 billion or 1000 x million tons), C = carbon (multiply by 3.6 to get mass in terms of CO2)].

Atmospheric CO2 growth
Annual mean growth rate of atmospheric CO2 was 2.2 ppm per year in 2007 (up from 1.8 ppm in 2006), and above the 2.0 ppm average for the period 2000-2007. The average annual mean growth rate for the previous 20 years was about 1.5 ppm per year. This increase brought the atmospheric CO2 concentration to 383 ppm in 2007, 37% above the concentration at the start of the industrial revolution (about 280 ppm in 1750).  The present concentration is the highest during the last 650,000 years and probably during the last 20 million years.

Emissions from land use change
Land use change was responsible for estimated net emissions of 1.5 PgC per year to the atmosphere. This is largely the difference between CO2 emissions from deforestation and CO2 uptake by reforestation. Emissions for 2006 and 2007 were extrapolated from the previous 25-year trend of 1.5 PgC per year. Land use change emissions come almost exclusively from deforestation in tropical countries with an estimated 41% from South and Central America, 43% from South and Southeast Asia, and 17% from Africa. An estimated 160 PgC were emitted to the atmosphere from land use change during the period 1850-2007.

Emissions from fossil fuel and cement
Emissions increased from 6.2 PgC per year in 1990 to 8.5 PgC in 2007, a 38% increase from the Kyoto reference year 1990. The growth rate of emissions was 3.5% per year for the period of 2000-2007, an almost four fold increase from 0.9% per year in 1990-1999. The actual emissions growth rate for 2000-2007 exceeded the highest forecast growth rates for the decade 2000-2010 in the emissions scenarios of the Intergovermental Panel on Climate Change, Special Report on Emissions Scenarios (IPCC-SRES). This makes current trends in emissions higher than the worst case IPCC-SRES scenario. Fossil fuel and cement emissions released approximately 348 PgC to the atmosphere from 1850 to 2007.

Regional fossil fuel emissions
The biggest increase in emissions has taken place in developing countries, largely in China and India, while developed countries have been growing slowly. The largest regional shift was that China passed the U.S. in 2006 to become the largest CO2 emitter, and India will soon overtake Russia to become the third largest emitter. Currently, more than half of the global emissions come from less developed countries. From a historical perspective, developing countries with 80% of the world’s population still account for only 20% of the cumulative emissions since 1751; the poorest countries in the world, with 800 million people, have contributed less than 1% of these cumulative emissions.

Carbon intensity of the economy
After decades of improvements, the carbon intensity of the global economy, the carbon emitted per unit of Gross Domestic Product (GDP), was stalled during the period 2003-2005. This change was largely caused by China’s rapidly growing share in economic output and carbon emissions. Since 2005 China’s energy intensity (which underpins carbon intensity) has decreased (improved) by 1.2% in 2006 and 3.7% in 2007 compared to 2005 levels (according to the National Energy Administration in China).

CO2 removal by natural sinks
Natural land and ocean CO2 sinks have removed 54% (or 4.8 PgC per year) of all CO2 emitted from human activities during the period 2000-2007. The size of the natural sinks has grown in proportion to increasing atmospheric CO2. However, the efficiency of these sinks in removing CO2 has decreased by 5% over the last 50 years, and will continue to do so in the future. That is, 50 years ago, for every ton of CO2 emitted to the atmosphere, natural sinks removed 600 kg. Currently, the sinks are removing only 550 kg for every ton of CO2 emitted, and this amount is falling.

Natural Ocean CO2 sinks
The global oceanic CO2 sink removed 25% of all CO2 emissions for the period 2000-2007, equivalent to an average of 2.3 PgC per year. The size of the CO2 sink in 2007 was similar to that in the previous year but lower by 0.1 PgC compared to its expected increase from atmospheric CO2 growth. This was due to the presence of a La Nina event in the equatorial Pacific. The Southern Ocean CO2 sink was higher in 2007 compared to 2006, consistent with the relatively weak winds and the low Southern Annular Mode (a circumpolar pressure oscillation between Antarctica and southern mid-latitudes). An analysis of the long term trend of the ocean sink shows a slower growth than expected of the CO2 sink over the last 20 years.

Natural Land CO2 sinks
Terrestrial CO2 sinks removed 29% of all anthropogenic emissions for the period 2000-2007, equivalent to an average of 2.6 PgC per year. Terrestrial ecosystems removed 2.9 PgC in 2007, down from 3.6 Pg in 2006, largely showing the high year-to-year variability of the sink. An analysis of the long term trend of the terrestrial sink shows a growing size of the CO2 sink over the last 50 years.

Conclusions. Anthropogenic CO2 emissions have been growing about four times faster since 2000 than during the previous decade, and despite efforts to curb emissions in a number of countries which are signatories of the Kyoto Protocol. Emissions from the combustion of fossil fuel and land use change reached the mark of 10 billion tones of carbon in 2007. Natural CO2 sinks are growing, but more slowly than atmospheric CO2, which has been growing at 2 ppm per year since 2000. This is 33% faster than during the previous 20 years. All of these changes characterize a carbon cycle that is generating stronger climate forcing and sooner than expected.

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