Climate Change 101: The Evidence Humans Aren’t Destroying the Climate
Written by H. Sterling Burnett
Climate change is real and has happened throughout history on local, regional, continent-wide, and global scales, driven by a variety of atmospheric, cosmic, geologic, and meteorological factors.
Beginning in the latter half of the 20th century, some scientists—and later environmental lobbyists and politicians—began to worry Earth was changing in ways detrimental to humans and the environment. As Earth cooled modestly from the 1940s through the late 1970s, scientists began to warn of—and headlines began to trumpet—the coming of the next ice age.
By the 1980s, however, the purported problem shifted, and scientists and environmentalists began to warn human-created greenhouse-gas emissions, primarily carbon dioxide resulting from burning fossil fuels, are warming the planet and that global warming would cause all manner of catastrophic climate changes—unless humans take extreme actions to stop it.
What We Know
Below, briefly, are the facts about greenhouse gasses and the purported human-caused global warming/climate change:
- Greenhouse gasses trap heat, making Earth habitable.
- Water vapor is the dominant greenhouse gas, making up 97–98 percent of the greenhouse gases in the atmosphere. Carbon dioxide and other trace greenhouse gases make up just 2–3 percent of all greenhouse gasses, and the share of carbon dioxide produced by humans is just a fraction of that.
- Earth came out of what some scientists refer to as the “Little Ice Age” in the early- to mid-1800s, decades before there was a rise in carbon-dioxide emissions, a pattern that historical analyses show is normal.
- Humanity’s share of carbon-dioxide emissions grew dramatically, beginning in the middle of the 20th century, with increasing industrialization.
- Although there are concerns about the soundness and consistency of the global system for measuring temperatures and disputes over possible data manipulation by various governments (due to the differences between measured and reported temperatures), the global average temperature has risen modestly since the 1880s, by about 1.4 degrees F, with approximately 40–50 percent of that warming occurring before the growth in greenhouse gases from human sources began.
Beyond these few statements, almost every other aspect of the climate change controversy is open to debate.
Differences between the claims made by those who believe in the theory human greenhouse-gas emissions significantly affect the climate and the actual measured changes strongly indicate humans are not causing a climate Armageddon and that climate alarmists’ theory is incorrect. In fact, based on the evidence, at the worst, humans are having a modest effect on Earth’s climate, with the increase in carbon dioxide possibly having a net beneficial effect (due to the enhanced plant productivity resulting from higher carbon-dioxide levels.)
There is no question humans have changed the climate on a regional scale—and not always for the better. In some places, deforestation and slash-and-burn farming have resulted in shifting rainfall patterns, flooding, and desertification. And where megacities have developed, ecosystems that previously existed no longer do, changing the course of rivers, draining underground aquifers, causing land subsidence, and contributing to flooding.
However, the evidence suggests human greenhouse-gas emission are having a limited impact on global climate, with virtually all the alarmists’ model predictions routinely failing to match reality. Anthropogenic warming theorists’ climate models assume temperatures should climb alongside rising carbon-dioxide levels, yet temperatures fell from the 1940s through the 1970s, even while emissions were rising dramatically. For the past two decades, carbon-dioxide levels have continued to increase, but global satellites have recorded no significant temperature increase for 18 years.
According to the average of all climate models, Earth’s temperature should be one degree F warmer now than what is currently being measured. The gap between measured temperatures and predictions is most likely due to the fact Earth is less sensitive to additional molecules of greenhouse gases than calculated by most climate models.
Climate models have assumptions built into their design concerning the secondary effects of carbon dioxide on Earth’s atmosphere, which they assume will enhance or amplify Earth’s warming. Simpler models that don’t build in these secondary effects track actual temperatures much more closely than the complex models do, and it’s the complex models upon which climate disaster projections are built.
Almost all the harmful impacts predicted by climate models are failing to materialize. For instance, climate models predicted more intense hurricanes, but for nearly a decade, the United States has experienced far fewer hurricanes making landfall than the historic average, and those hurricanes that have made landfall have been no more powerful than previously experienced.
Additionally, while scientists have claimed anthropogenic warming should cause sea levels to rise at increasing rates—because of melting ice caps in Greenland and Antarctica and the thermal expansion of water molecules under warmer conditions—sea-level rise has slowed. Sea levels have always risen between ice ages or during interglacial periods. Indeed, sea levels have risen more than 400 feet since the end of the last interglacial period. However, the rate of sea-level rise since 1961 (approximately one-eighth of an inch per year) is far lower than the historic average (since the end of the previous ice age), and sea-level rise has not increased appreciably over the past century compared to previous centuries. Also, measured seal-level rise is well below the rise predicted by those climate models claiming sea levels would increase because of anthropogenic warming.
While some locations have experienced dramatic sea-level rise and unexpected flooding, the reason is not anthropogenic greenhouse-gas emissions; it’s often because of other human causes. For instance, in many of these locations, land subsidence—due to increased withdrawals from shore adjacent to aquifers—is the problem.
Further, many people are now building in locations prone to flooding—such as in areas near wetlands and in marshy areas, which historically mitigated or buffered mainland locations from flooding. There are a variety of reasons this is happening, but one of the most important is many government insurance programs (and other government programs, too) subsidize building in areas prone to flooding or hurricane damage.
Based on climate models’ projections of land and ecosystem shifts and changes, biologists have predicted anthropogenic warming would cause numerous plant and wildlife extinctions, yet they have been unable to point to a single instance of a species going extinct due to human-caused climate change thus far.