IPCC Fifth Assessment Report: Climate Change Nearly Irreversible; Man Is The Cause

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Global air and sea temperature for January through September, 2014 were the highest ever. Analysis courtesy of NOAA

Global air and sea temperature for January through September, 2014 were the highest ever. Analysis courtesy of NOAA

On November 1, the Intergovernmental Panel on Climate Change (IPCC) issued its 5th Assessment Report (AR5). Some of the conclusions are worth noting.

The Synthesis Report condenses the findings of thousands of scientific papers into 100 pages that describe the latest science concerning anthropogenic global warming.

AR5 is a stark warning about the future of the planet if greenhouse gases continue to be spewed into the environment unchecked. But it is also a capitulation to reality comprising four sections, two of which are devoted to adaptation to, and mitigation of, the effects of climate change.

The other two sections discuss the current state of affairs, and the future under various scenarios.

Who Is On The Panel — And Who Is Not

Climate-change deniers make much of the fact that this is an intergovernmental panel. The insinuation is that anything to do with government is bad. But this panel includes over 800 scientists; many of them are the world’s most respected earth scientists in their disciplines.

As a subterfuge, die-hard deniers have set up a sham organization called the Nongovernmental Independent Panel on Climate Change (NIPCC). The members of this panel have little expertise and spout the party line. Many of the articles on their website are unattributed except to list editors by last name and first and middle initial. It is impossible to find background on many of them.

Yet even hard-core skeptics appear to have thrown in the towel on global warming and greenhouse gases. The pages of their websites are filled with articles about the beneficial effects of warmer global temperatures and increased amounts of carbon dioxide in the atmosphere and oceans.

What The IPCC Report Says

The steady increase in atmospheric carbon dioxide. Graphic courtesy of NOAA

The steady increase in atmospheric carbon dioxide. Graphic courtesy of NOAA

AR5 does not pussyfoot around the issues. The conclusions are not couched in statistical jargon. Nor is there any equivocation about the cause of climate change:

From the report: “Warming of the climate system is unequivocal.” And further: “Human influence on the climate system is clear.” These statements are straightforward and their meaning cannot be mistaken.

The report details the conclusions of hundreds of scientific papers. The evidence is massive and overwhelming.

Again from the report: “Historical emissions have driven atmospheric concentrations of carbon dioxide, methane and nitrous oxide to levels that are unprecedented in at least 800,000 years.”  

This has led to “warming of the atmosphere and the ocean, changes in the global water cycle, reduction in snow and ice, and global sea-level rise.”

The Human Response

Much of AR5 is devoted to the response at national and international levels to what is happening to the climate. That response is acknowledged to be short on remedy at the root cause — reduction of greenhouse gas (GHG) emissions. Rather, the response has been acceptance, adaptation, and mitigation.

Again from the report: “Adaptation and mitigation experience is accumulating across regions and scales, even while global anthropogenic GHG emissions have continued to increase.”  The resignation to the inevitable future is palpable.

Warnings from scientists have been ignored in the past. The question now is how much damage will be done: “Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems.”

Looking Further Into The Future

The panel comes to the conclusion that even with extreme reductions of GHGs immediately, the results of the current elevated levels will last for a long time: “Many aspects of climate change and its impacts will continue for centuries, even if anthropogenic emissions of greenhouse gases are stopped. The risk of abrupt or irreversible changes increase as the magnitude of the warming increases.”

Mitigation And Adaptation

Though the panel urges immediate drastic reductions in emissions of GHGs, they recognize the inertia of governments preoccupied with other matters of immediate political importance. Thus the report devotes much of its space to the cost and effectiveness of various mitigation and adaptation techniques. They warn that these have risks also, but believe that the risks associated with inaction are much greater.

Prediction of temperature in 2100 by the Geophysical Fluid Dynamics Laboratory model. Graphic courtesy of GFDL

Prediction of temperature in 2100 by the Geophysical Fluid Dynamics Laboratory model. Graphic courtesy of GFDL

“Without additional mitigation efforts beyond those in place today, and even with adaptation, warming by the end of the 21st century will lead to high to very high risk of severe, widespread, and irreversible impacts globally. Mitigation involves some level of co-benefits and risks due to adverse side-effects, but these risks do not involve the same possibility of severe, widespread, and irreversible impacts as risks from climate change, increasing the benefits from near-term mitigation efforts.”

The report concludes that to reach the modest goal of limiting warming to five degrees Fahrenheit would require a reduction in GHG emissions to near zero by the end of the century.

In what seems like rather an understatement, the report says: “Implementing such reductions poses substantial technological, economic, social, and institutional challenges.”

Rising To The Occasion And Meeting The Challenge

AR5 lays out clearly the implications of GHG emissions and climate change. There is no indication as yet that the citizens of the world have been listening to previous warnings. Humanity has a penchant for brinksmanship — inertia rules until there is no alternative but to move.

Currently there is a stalemate between developed nations which refuse to reduce their overweighted share of global emissions and developing nations that want to increase theirs. A compromise awaits statesmanship.

Though the prospects currently look bleak, Homo sapiens has responded to crises in the past: Nuclear arms control and banning of ozone-depleting CFCs are the best examples. The former was the solution to an existential threat, while the latter required only minor technical innovations.

Come back in a couple of hundred years and see how this works out.

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