Climate change
Updated: 25 March 2010, 03:33
Originally written: 03 February 2007
In the first-released section of its Fourth Assessment Report, Working Group I of the Intergovernmental Panel on Climate Change says that global warming is reality. The IPCC Summary for Policymakers states:
In the light of new evidence and taking into account the
remaining uncertainties, most of the observed warming over
the last 50 years is likely to have been due to the increase in
greenhouse gas concentrations.
Furthermore, it is very likely
that the 20th century warming
has contributed significantly to the observed sea level rise,
through thermal expansion of sea water and widespread loss of
land ice. Within present uncertainties, observations and models
are both consistent with a lack of significant acceleration of
sea level rise during the 20th century.
An expanded version of the summary report is also available.
Referring to the current century (2001-2100), the report tells us:
- Emissions of CO2 due to fossil fuel burning are virtually certain to be the dominant influence on the trends in atmospheric CO2 concentration during the 21st century.
- The projected rate of warming is much larger than the observed changes during the 20th century and is very likely to be without precedent during at least the last 10,000 years, based on palaeoclimate data.
- The globally averaged surface temperature is projected to increase by 1.4 to 5.8°C over the period 1990 to 2100.
- Temperature increases are projected to be greater than those suggested in the previous (2001) report.
- On timescales of a few decades, the current observed rate of warming can be used to constrain the projected response to a given emissions scenario despite uncertainty in climate sensitivity. This approach suggests that anthropogenic warming is likely to lie in the range of 0.1 to 0.2°C per decade over the next few decades under one scenario.
- Based on recent global model simulations, it is very likely that nearly all land areas will warm more rapidly than the global average, particularly those at northern high latitudes in the cold season. Most notable of these is the warming in the northern regions of North America, and northern and central Asia, which exceeds global mean warming in each model by more than 40%. In contrast, the warming is less than the global mean change in south and southeast Asia in summer and in southern South America in winter.
- Based on global model simulations and for a wide range of scenarios, global average water vapour concentration and precipitation are projected to increase during the 21st century. By the second half of the 21st century, it is likely that precipitation will have increased over northern mid- to high latitudes and Antarctica in winter. At low latitudes there are both regional increases and decreases over land areas. Larger year to year variations in precipitation are very likely over most areas where an increase in mean precipitation is projected.
- Global mean sea level is projected to rise by 0.09 to 0.88 metres between 1990 and 2100, ... due primarily to thermal expansion and loss of mass from glaciers and ice caps.
The IPCC tells us now:
Since the release of the Second Assessment Report (SAR), additional data from new studies of current and palaeoclimates, improved analysis of data sets, more rigorous evaluation of their quality, and comparisons among data from different sources have led to greater understanding of climate change.
and thatThe SAR concluded: “The balance of evidence suggests a discernible human influence on global climate”. That report also noted that the anthropogenic signal was still emerging from the background of natural climate variability. Since the SAR, progress has been made in reducing uncertainty, particularly with respect to distinguishing and quantifying the magnitude of responses to different external influences. Although many of the sources of uncertainty identified in the SAR still remain to some degree, new evidence and improved understanding support an updated conclusion.
The current report also says:
- There is a longer and more closely scrutinised temperature record and new model estimates of variability. The warming over the past 100 years is very unlikely to be due to internal variability alone, as estimated by current models. Reconstructions of climate data for the past 1,000 years also indicate that this warming was unusual and is unlikely to be entirely natural in origin.
- There are new estimates of the climate response to natural and anthropogenic forcing, and new detection techniques have been applied. Detection and attribution studies consistently find evidence for an anthropogenic signal in the climate record of the last 35 to 50 years.
- Simulations of the response to natural forcings alone (i.e., the response to variability in solar irradiance and volcanic eruptions) do not explain the warming in the second half of the 20th century. However, they indicate that natural forcings may have contributed to the observed warming in the first half of the 20th century.
- The warming over the last 50 years due to anthropogenic greenhouse gases can be identified despite uncertainties in forcing due to anthropogenic sulphate aerosol and natural factors (volcanoes and solar irradiance). The anthropogenic sulphate aerosol forcing, while uncertain, is negative over this period and therefore cannot explain the warming. Changes in natural forcing during most of this period are also estimated to be negative and are unlikely to explain the warming.
- Most of these studies find that, over the last 50 years, the estimated rate and magnitude of warming due to increasing concentrations of greenhouse gases alone are comparable with, or larger than, the observed warming. Furthermore, most model estimates that take into account both greenhouse gases and sulphate aerosols are consistent with observations over this period.
- The best agreement between model simulations and observations over the last 140 years has been found when all the above anthropogenic and natural forcing factors are combined, these results show that the forcings included are sufficient to explain the observed changes, but do not exclude the possibility that other forcings may also have contributed.
Those scientists could be wrong. If they are correct, and ignored, the results are likely to be disastrous.
Particularly frightening is that the scientists report that “anthropogenic climate change will persist for many centuries” after humans address the causes. That means that yesterday’s CO2 will affect us for generations, and we still have not dealt with today’s CO2.
Even Canada’s Prime Minister Stephen Harper, and U.S. President George Bush, appear to be jumping on the global warming bandwagon. It appears that the electorate, again, is forcing the politicians to at least pretend to act.
But that is the problem. They pretend to act. The previous Liberal Party governments of Canada pretended to support the Kyoto accord, but greenhouse gas emissions in Canada increased steadily, rather than declining. So, instead of six percent below 1990 levels, the Liberals were kicked out of office after permitting the emissions to increase by about 35 percent.
Because the government must govern for the capitalist class, and because most people strongly support capitalism, any attempt to address the problem must compete with capitalism’s need for increasing profit. For years we have been told, especially by people such as Stephen Harper, and influential newspapers such as the National Post, that any attempt to actually reduce production of greenhouse gases would be economic suicide.
Environmentalists have talked about economic benefits of dealing with greenhouse gases. Their explanations have been unconvincing.
Any serious attempt, under capitalism, to deal with the problem will be extremely expensive, adding to the cost of production, and perhaps forcing certain production to end, along with any related jobs. Even if capitalism does attempt to deal with the problems, eventually, it will be too little, too late, as always.
A socialist society will have huge advantages when dealing with global warming and other pollution. For example, establishing socialism would mean eliminating the need for war. That would mean that the production for war could cease, immediately, along with any attendant global warming caused by that production. There are also other, much more obvious, benefits to ending war.
Unlike today, a socialist society will not have to beg the rich to choose safer technology. We will simply choose the best, because there will be no profit motive to interfere with common sense.
Perhaps it is already too late to correct the damage to our ecosystem. The choice is simple: give up and slide further into oblivion, or establish an economic structure and social organisation which will permit us to use our common sense, and enable a solution.
