Climate Change - an Introduction

October 05, 2021 • Larry Kane

"The work of conservation is inspired by wonder, gratitude, reason, and love.   . . .  But the first impulse is love - love for wild and settled places, for animals and plants, for people living now and those yet to come . . .  ."  

"A Conservationist Manifesto"  by  Scott Russell Sanders  

Imagine a mid-July, 2060, in Chicago, Illinois, where beleaguered residents, numbering over 4 million, are sweltering with midsummer heat over 105°F. Such extreme temperatures, unheard of 40 years ago, have become all too common over past decades. Overloading of the antiquated electric grid from continual operation of residents' air conditioners and service interruptions from a higher incidence of severe storms have combined to produce frequent brown-outs of electrical service. Over 3,000 lower income Chicagoans have died already this summer as a result of heat exhaustion when brownouts lasted too long. In the evenings your grandchildren watch news reports of wildfires consuming hundreds of millions of acres of forested land in California, Oregon and southern Idaho. The drought conditions in California and other parts of the western U.S. have become so pervasive and routine that millions of people have abandoned their homes and moved to crowded slum-like conditions in the large cities of the Midwest and eastern U.S. Only a paltry fraction of agrarian acreage of the Great Plains states can still support grain farms and confined cattle feeding operations because the last vestiges of the Ogallala aquifer - once considered an inexhaustible source of groundwater - are nearing depletion. As a result, food prices have increased tenfold in the past 20 years. Seafood is affordable for most families only once a month, if available at all, since the once plentiful fisheries of the Atlantic and Pacific Oceans have been largely depleted. Coral reefs, once vital nurseries for fisheries, largely died off in the 2030s.         

The grim fictional future described above may seem farfetched but is supported in concept by climatologists' projections of the adverse impacts of climate change if effective counter-measures are not initiated promptly to mitigate this manmade catastrophe. In some parts of the world, extreme temperatures are already occurring. Among the worst is Jacobabad, Pakistan (located in lowlands roughly 50 km northwest of the Indus River in south central Pakistan), where the number of days each year with temperature highs of 50° C (122° F) or more have increased to "months" and, unsurprisingly, residents are dying from heat exhaustion or heatstroke during such extreme conditions.[1] 

Reports raising alarm about impending effects of a changing climate and its serious repercussions for humanity first began to emerge in the early 1980s and have appeared with increasing frequency and urgency over the past twenty years. But mankind has not been listening! As a result of stark partisan disagreements, no meaningful concerted action has taken place in the U.S. at a national level to avert this looming disaster.  

Critical questions need to be confronted: What is "climate change"? Will it actually happen? How and why does it occur? How serious are the implications? Should we really be concerned? In this and subsequent posts, we provide basic information responding to these and other questions so that you can begin to assess the significance of climate change. And, yes, this is important! Our children's future lies in the balance - actually, it is in our hands. 

What Is Climate Change? 

First, some terminology:  the terms "climate" and "weather" need to be distinguished.  We talk every day about the "weather", which refers to short term conditions such as how warm or cold it will be tomorrow, whether it will be sunny or overcast, whether it will rain or snow, and whether severe storms are impending. "Climate," on the other hand, refers to the long-term trend of weather conditions, usually over a period of 30 years or more. "Climate change," then, refers to a significant change in the long-term trend.   

The core concern posed by climate change involves the predicted warming of the Earth's surface and lower atmosphere. These predictions derive from the natural phenomenon known as the "Greenhouse Effect". This term refers to the ability of certain atmospheric gases, including carbon dioxide, methane, nitrous oxide and water vapor, known popularly as "greenhouse gases" (GHGs), to trap and retain some heat resulting from solar radiation that otherwise would re-radiate back into space.[2] Following is a simplified explanation of how it works:   

Solar radiation naturally warms the land masses and oceans of the Earth's surface. A fraction of the heat generated on the surface radiates back into the atmosphere as infrared radiation and would escape into outer space in the absence of GHGs. (See illustration below.) However, the presence of GHGs in the lower atmosphere acts as a heat trap that prevents escape from the Earth of a portion of the heat radiating upward from the surface. Some of the heat trapped by GHGs then radiates back toward Earth's surface, producing higher surface temperatures than would otherwise exist.  


Ironically, the Earth would not be warm enough for habitation without this phenomenon as it operates under natural conditions. BUT we are no longer experiencing natural conditions, as explained below, and the greenhouse effect is now threatening to produce higher temperatures dangerous to earthly life forms, including humans.  

As atmospheric concentrations of GHGs increase, the heat-trapping capability of the greenhouse effect is enhanced and warming of the Earth increases commensurately, This cause-and-effect relationship becomes of particular concern as we consider the remarkable rise in levels of carbon dioxide (CO2) over the past century as described in the following section.[3]  

Is Climate Change Likely? 

Atmospheric levels of CO2 remained at or below 280 parts per million (ppm) throughout mankind's existence until the industrial revolution was well underway in the early to mid- 19th century.[4]  Then it began to rise.  

Monitoring of atmospheric CO2 shows average global concentrations of CO2 initially rose rather  slowly, increasing from 290 ppm in 1880 to about 315 ppm in 1960, but then much more rapidly to 390 ppm in 2010. The atmospheric CO2 level has continued to grow rapidly (exponentially) to 400 ppm in 2016 and then to 415 ppm in May, 2019.[5] The current level is reported to be the highest in more than a million years.  

Empirical data provide cogent evidence that climate change is already happening. Under the influence of the greenhouse effect, mean global temperatures at the Earth's surface have risen on a trajectory similar to that of increasing atmospheric levels of CO2. They have increased about 1.98°F (1.1°C) between 1900 and 2020 (with land regions generally experiencing higher increases in temperature than the mean global temperature increase). Globally, the years from 2015 through 2020 are the hottest on record. Related impacts that have been observed over the past 30 years include: increasing warming and acidification of ocean waters due to absorption of heat and CO2 from the increasing atmospheric levels; increasing severity of violent storms, especially over the past 10 to 15 years; and significant melting of ice cover in the Arctic Ocean, as well as of glaciers in Greenland, the Canadian Rockies, the Alps and the Himalayan Mountains.  

More detailed information on projected future impacts of climate change will be highlighted in future articles.   

Why Is Climate Change Occurring?  

Given the compelling evidence that climate change, driven by global warming, is already happening, we need to consider a critical question: why is it occurring?  The great majority of climate scientists have concluded that the current climate change phenomenon is primarily a result of human activities. The chief cause has been identified as the combustion of fossil fuels, particularly coal, although other activities such as deforestation and inefficient generation and use of energy are contributing factors. For example, beginning with its First Assessment Report issued in 1990, the UN’s Intergovernmental Panel on Climate Change (IPCC) [6] concluded with certainty that the increasing emissions of GHGs resulting from human activities, such as fossil fuel combustion, are causing substantial increases in atmospheric concentrations of GHGs. There is no credible alternative explanation for the inexorable rise in atmospheric CO2 levels to a point unprecedented in the past million years of Earth's existence. The IPCC has further concluded that the increasing atmospheric levels of CO2 are, in turn, producing increased warming of Earth's surface via the greenhouse effect. Thus, the natural greenhouse effect has been transformed into an "unnatural" weapon that we unwittingly have turned against ourselves and the natural ecosystems of the Earth.   

More to come. Subsequent posts will provide further information on the effects of climate change, the origins of climate denial, and, more importantly, an overview of actions we can take to arrest the course of climate change.  


[1] The Hottest City on Earth, A. Baker, Time Magazine Special Climate Issue, September 23, 2019, at 38.  

[2] More specifically, incoming solar radiation, consisting mainly of visible light, infrared radiation, and ultraviolet radiation, passes through the atmosphere, which is largely transparent to this radiation, to reach the Earth's surface, where it produces heat. Some of that heat is radiated back into the atmosphere as infrared radiation, which has a much longer wavelength than most of the incoming solar radiation. Greenhouse gases ("GHGs") are particularly capable of absorbing this infrared radiation, which causes heating of the gas molecules. This increased heat energy results in the re-emission of infrared radiation, some of which is directed back into the lower atmosphere and the earth's surface, where it causes further warming.  

[3] Atmospheric concentrations of other GHGs such as methane and nitrous oxide have also been increasing over the past century but at considerably slower rates  

[4] Living in the Environment, p. 497, G. Tyler Miller, et al., 2012 Brooks/Cole.  

[5] The Science Times, May 17, 2019.  

[6] The IPCC is an ancillary body of the United Nations whose responsibility is to assess scientific literature on climate change published by researchers and to prepare periodic consensus summaries of the current state of scientific knowledge. Six assessment reports have been issued, with the most recent published in 2021.    

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Larry Kane