Climate Change 101: The Evidence Humans Aren’t Destroying the Climate

By. H. Sterling Burnett, Ph.D.

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.)

Climate Models

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.

Failed Predictions

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.

For instance, although sea ice in the Arctic has declined over the past 20 years, polar bears—which various scientists predicted would be driven to extinction due to declining sea-ice levels (shrinking sea ice limits their ability to capture seals)—have proven highly adaptable. Their populations have grown dramatically over the past 60 years, from approximately 5,000 bears in the 1950s to more than 25,000 today. In the few locations in which populations have declined, temperatures have been cooler, not warmer than average, during the past few decades.

Scientists have also claimed anthropogenic climate change is causing the oceans to warm and become more acidic. They point to widespread coral bleaching and coral reef “deaths” as proof and as a warning of the worsening conditions that will come if the global warming problem isn’t solved immediately. However, as with the alleged polar-bear extinction crisis, the rumors of coral reefs’ deaths have been greatly exaggerated. Coral reefs evolved during and survived through several more-dramatic climate shifts than the one the world is currently undergoing, and they have proven much more resilient than climate alarmists have claimed.

Pollution, not climate change, has harmed many reefs, but in those cases, as with other reefs that bleached in recent years for reasons that have yet to be explained, researchers have found many reefs are recovering and now have new corals forming. While newspapers are calling this recovery miraculous, I prefer to think of it as further evidence we know little about many features of the natural world. Anyone who thinks he or she can attribute the harm caused to ecosystems or their component species to the single factor of human-caused climate change is suffering from extreme hubris.

Contradicting climate models once again, Antarctica is gaining tens of thousands of tons of ice each year, even as some ice-shelves collapse. In addition, in the past few years, despite a warmer world, sea-ice extent in Antarctica has repeatedly grown at a rapid pace, smashing previous records several times.

And while some climate pessimists point to a few outlier research papers claiming climate change will lead to a decline—or even an outright collapse—of major agricultural crops, mainstream agronomists are optimistic about the agricultural outlook under altered climate conditions. After all, most of the world’s plants evolved during periods when global carbon-dioxide levels were much higher than they are today or are expected to be in the foreseeable future. As carbon dioxide has increased, plant life—both agricultural and non-agricultural plants—has become more fecund, with crop production regularly setting records year over year.

The latter should not be a surprise, as agronomists have long recognized carbon dioxide acts as a plant fertilizer, which is why they artificially increase it in greenhouses. Under higher-carbon-dioxide conditions, plants grow faster, more abundantly, and use water more efficiently. Only climate pessimists firmly caught up in the grips of their flawed theory could fail to foresee this beneficial outcome of growing carbon-dioxide levels.

An Always-Changing Climate

In his brilliant book The Moral Case for Fossil Fuels, Alex Epstein writes:

“Climate is no longer a major cause of death, thanks in large part to fossil fuels. … Not only are we ignoring the big picture by making the fight against climate danger the fixation of our culture, we are “fighting” climate change by opposing the weapon that has made it dozens of times less dangerous. The popular climate discussion has the issue backward. It looks at man as a destructive force for climate livability, one who makes the climate dangerous because we use fossil fuels. In fact, the truth is the exact opposite; we don’t take a safe climate and make it dangerous; we take a dangerous climate and make it safe.”

Earth’s climate is changing, as it always has, but humanity’s role in that change and whether it will produce great harms or, on balance, net benefits is very much open to debate. At the same time, there is no question fossil-fuel use makes us wealthier, and wealthier societies are better able to anticipate, mitigate, adapt, and respond to the vagaries of climate change, regardless of the cause or type of change.

Sterling Burnett, Ph.D. ([email protected]) is a research fellow on energy and the environment at The Heartland Institute, a nonpartisan, nonprofit research center headquartered in Arlington Heights, Illinois.



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