Earlier this week President Obama and other world leaders addressed participants of the latest United Nations conference on climate change in Paris (COP21), where they lent their support for a new legally-binding agreement to reduce greenhouse gas emissions. Given statements they made about both the causes and consequences of climate change, it is clear that what the world's leaders truly need is not another climate treaty, but a whole lot more common sense in evaluating this issue for our time.
Take, for example, a line early on in President Obama's speech1 in which he said that "fourteen of the fifteen warmest years on record have occurred since the year 2000." Though global temperatures are indeed presently warm within the context of the past century, there has been little to no increase in global temperature over the past eighteen years despite an eight percent rise in atmospheric CO2. Furthermore, much evidence indicates that today's warm temperatures remain below peak temperatures experienced during the Medieval Warm Period of 1,000 years ago,2 the Roman Warm Period of 2,000 years ago3 and the Holocene Climatic Optimum of 5,000 years ago.4 What is more, going further back in time, each of the preceding four interglacial periods (for which high-quality reconstructed temperature records exist) were more than 2°C warmer than the interglacial in which we currently live.5 And because atmospheric CO2 concentrations during all four prior interglacials never rose above approximately 290 ppm, whereas the air's CO2 concentration stands at about 400 ppm today, common sense tells us that if there is anything unusual, unnatural, or unprecedented about current air temperatures, it is that they are so low in the presence of such high CO2 concentrations, if one believes that CO2 is the all-important driver of climate change that the President and others attending COP21 make it out to be.
President Obama's speech could have benefited from a little more common sense at several other junctures as well. Embracing an alarmist view of the future, the President claimed CO2-induced climate change will lead to "submerged countries," "abandoned cities," "fields that no longer grow," "political disruptions" and "more floods." Though each of these outcomes are indeed projected to occur in some climate model simulations, there are numerous reasons to doubt those projections.
One recent study,6 for example, presented a thorough and careful scrutiny of hundreds of peer-reviewed scientific publications evaluating the accuracy and capability of climate models to simulate the response of a number of important climatic phenomena to rising atmospheric CO2 concentrations. In short, that treatise provided the proverbial under-the-hood look at the inner workings of today's state-of-the-art climate models that provide the basis for the belief that global warming is a problem and that something must be done about it. And that "look" was not encouraging. It documented a total of 2,418 failures of today's top-tier climate models to accurately hindcast a whole host of climatological phenomena.
With that extremely poor record of success, one must seriously wonder how it is that any person or government would believe what the climate models of today project about Earth's climate of tomorrow, i.e., a few decades to a century or more from now, and then seek to formulate policy based on that output. Common sense suggests it to be the height of folly to place any faith whatsoever in the predictions of even the very best of today's most up-to-date climate models in a future atmospheric-CO2-enriched world.
Another common sense reason for rejecting the President's alarmist (and model-based) vision of Earth's climatic future is that they are unsupported by numerous observations. Consider the President's worry of "submerged countries." Global sea levels have been rising since the glacial maximum of the last ice age some 18,000 years ago, but observations indicate that the rate of sea level rise is not accelerating and may even be decelerating.7 What is more, multiple studies reveal the stability of small-island States, many of which are not losing, but actually gaining, ground despite continued sea level rise.8
The President is also wrong on his projection of floods. Contrary to model projections, there is no evidence that floods are increasing in frequency or intensity as a result of human emissions of greenhouse gases.9 Neither is there any compelling evidence to support a CO2-induced increase in droughts, storms, hurricanes, or other manifestations of extreme weather event.10 And as for "political disruptions," a relationship between climate and war or social unrest has indeed been established, just not the relationship envisioned by President Obama. Multiple research papers have documented that colder climates are far more likely to cause civil unrest and strife than warmer climates, the latter of which tend to foster growth, prosperity and peace.11
With respect to "abandoned cities," the President could benefit from some common sense, such as I have learned while living in the metropolitan Phoenix area over the past five decades. Despite a very warm desert climate and a growing urban heat island that has raised city temperatures by several degrees Celsius over the past half-century, the population here continues to grow by leaps and bounds, which growth is primarily sustained from migrants who are choosing to leave colder locations for the warmer weather of metro Phoenix! Given modern technological advances such as air conditioning that allow societies to adapt and cope with living in a warm environment, it is highly unlikely cities like Phoenix will become abandoned in the future if the temperature were to warm even a few more degrees.
The President could also have benefited from some simple common sense about the impact of rising CO2 on plant life, for in applying such, he certainly would not have claimed that atmospheric CO2 is "carbon pollution" and that climate change will lead to "fields that no longer grow."
It used to be (at least when I was in school) that such common sense was instilled by the 4th or 5th grade when students were taught that atmospheric CO2 is the building block of plant life. It is the primary raw material used by them in the process of photosynthesis to construct their tissues and grow. And as has been conclusively demonstrated in literally thousands of scientific studies, the more CO2 we put into the air, the better plants grow, producing greater amounts of biomass and becoming more efficient at using water, and better able to cope with environmental stresses such as pollution and high temperatures.12
Altogether, therefore, common sense suggests that with the plant productivity gains that result from the aerial fertilization effect of the ongoing rise in atmospheric CO2, plus its transpiration-reducing effect that boosts plant water use efficiency, along with its stress-alleviating effect that lessens the negative growth impacts of resource limitations and environmental constraints, the world's vegetation possesses an ideal set of abilities to reap a tremendous benefit from what the President inaccurately terms "carbon pollution" in the years and decades to come. And based on a multitude of observations, that future is now -- as evidence from across the globe indicates the terrestrial biosphere is presently experiencing a great planetary surge in growth, likely due in large measure to the approximate 40% increase in atmospheric CO2 that has occurred since the beginning of the Industrial Revolution.13
With respect to all land plants, for example, satellite-based studies reveal net terrestrial primary productivity has increased by 6-13% since the 1980s.14 Other research shows the annual global carbon uptake has doubled from 2.4 ± 0.8 billion tons in 1960 to 5.0 ± 0.9 billion tons in 2010.15 What makes these observations appear even more astonishing, however, is the fact that they have occurred despite the many recorded assaults of both man and nature on planetary vegetation over this time period, including fires, disease, pest outbreaks, deforestation, and climatic changes in temperature and precipitation. That the biosphere experienced any productivity improvement at all, let alone a doubling, is truly amazing; and it demonstrates in part the powerful impact atmospheric CO2 enrichment is exerting on Earth's vegetation.
The implications of these benefits are enormous. One recent study calculated that over the 50-year period ending in 2001, the direct monetary benefits conferred by the atmospheric CO2 enrichment of the Industrial Revolution on global crop production amounted to a staggering $3.2 trillion.16 And projecting this positive externality forward in time reveals that, rather than leading to "fields that no longer grow," it will likely bestow an additional $9.8 trillion in crop production benefits between now and 2050.
In light of all of the above demonstrable facts, when it comes to the issue of climate change, it would appear that all that our world leaders need is a little more common sense, in order to avoid the nonsense of seeking a globally-binding treaty to reduce CO2 emissions. Indeed, it is high time for them, and for all of us, to recognize and embrace the truth. Contrary to misguided assertions, political correctness, and government edicts, carbon dioxide is not a pollutant. Its increasing concentration only minimally affects Earth's climate, while offering tremendous benefits to the biosphere. Efforts to regulate and reduce CO2 emissions are simply ludicrous. They will hurt far more than they will help.
5. See Section 4.2.1, The Warmth of Prior Interglacial Climates, Climate Change Reconsidered II: Physical Science, http://www.nipccreport.org/reports/ccr2a/pdf/Chapter-4-Temperature.pdf
8. See many examples at http://www.co2science.org/subject/s/sealevelsmall.php
9. See Section 7.5, Observations: Extreme Weather, Climate Change Reconsidered II: Physical Science, http://www.nipccreport.org/reports/ccr2a/pdf/Chapter-7-Extreme-Weather.pdf
12. See Climate Change Reconsidered II: Biological Impacts, http://www.nipccreport.org/reports/ccr2b/ccr2biologicalimpacts.html