Approaching climate change with caution

How has our knowledge of climate breakdown changed over time, and what is it that's tempering our language and inhibiting decisive action?


The impacts of climate change caused by global warming have become graphically evident in the last 20 years.

Record high temperatures have been twice as frequent as record low temperatures, and 17 of the 18 warmest years in recorded history occurred in the last 19 years.  The consequences are death, injuries, and catastrophic economic losses to tens of millions of people around the world.

News reports on the latest disasters show massive forest fires in California and unprecedented flooding in the Midwest. They don’t show less photogenic effects, like inevitably melting glaciers and declining marine fisheries, nor completely invisible consequential effects, like diverting public funds from building better schools and hospitals to replacing storm-damaged housing, roads and bridges.

Predicting danger

Worse, the destructive events we’ve seen are not a “new normal” – the damage will intensify as the years pass. The carbon dioxide (CO2) emitted during the twentieth century, combined with our much larger current emissions, will cumulate to increase the average global temperature year after year.

Why are we only now recognizing the predicted dangers?

Scientists theorized that increases in atmospheric CO2 could cause an unprecedented increase in the earth’s temperature as early as the 1850s. But the timing and practical impacts were an enigma.

By the 1970s, satellites and other scientific tools began providing real-world data that made some rough predictions possible.

In 1988, the United Nations created an Intergovernmental Panel on Climate Change (IPCC) to build an international consensus on the threat.

Uncertain language 

The record shows that the IPCC climate scientists insisted on too much certainty, understated the human and social consequences of climate change, and engaged in optimistic, perhaps magical thinking about the risks of irreversible disaster for civilization.

The First IPCC Report in 1990 was hardly an urgent call for action. It estimated the most likely global average temperature increase, compared to 1990, would be about 1o Celsius [1.8o Fahrenheit] by 2025 and about 3o C [5.4o F] by 2100.

Moreover, its summary stressed uncertainty about its conclusions: the warming “could be largely due to natural variability”, and “the unequivocal detection of the . .  . effect from observations is not likely for a decade or more.”

“Great uncertainties remain with regard to the timing, magnitude and regional impacts…”

This language could easily be read as only suggesting more research.  

Treading cautiously

The Fifth IPCC Report in 2014 contained much more concrete projected temperature increases. It anticipated a most likely average temperature increase of 4.0o C [7.2o F] by 2100.

But this report presented the likely effects in non-emotive terms: for example, it said “sea-level rise and storms could lead to significant movements of people”, instead of a more graphic, and accurate, statement like “millions of poor, uneducated farmers and fishermen will become refugees seeking new homes in more developed countries.”

The scientists involved still stressed the hopeful side of the probabilities. They didn’t point out that there is  a 35 percent or 40 percent chance of much higher temperatures that could destroy civilization – less probable than the median temperature rise projection, but a risk of unacceptable catastrophe.

So why were the IPCC scientists still so cautious in 2014?

The scientists’ statistical concept of “confidence” is far more demanding than what most non-scientists consider sufficient. They were reluctant to recommend drastic, disruptive economic restructuring to end fossil-fuel emissions without being absolutely positive their predictions were correct. Only in 2019 did the three best climate models all confirm a greater than 99.9 percent likelihood that global warming is human-induced.

Reputation for objectivity 

Added to this, the dominant scientific disciplines of IPCC members were climate science and meteorology –– not biology, ecology, economics, or social science.

These climate scientists focused on the most certain danger: rising sea levels over time. Possible societal effects were glossed over.  

IPCC Report conclusions are inevitably watered down to obtain consensus (virtual unanimity) among all participating scientists. Some participants from oil-dependent countries seemed to lean toward protecting their economic interests.  

Finally, scientists try to avoid “alarmist” talk about global warming consequences that would sound “unscientific” or “political” and taint their reputation for objectivity.

This reluctance, combined with the human tendency toward optimism, discourages them from saying “the end of civilization is coming.”

Destructive force 

The Fifth IPCC Report also confirmed that the use of fossil fuels was dramatically expanding, not declining.

Meanwhile, biologists and social scientists had begun ringing alarm bells. They saw the impacts everywhere: falling agricultural yields, disappearing fisheries, coastal flooding, extreme storms, species extinctions, melting glaciers, and collapsing water supplies.

Most prominently, they identified the multi-year droughts in Somalia and Syria as the underlying cause of famines, civil and international violence, and massive migrations toward Europe.

Hurricane Sandy brought home the destructive force of storm surge for New York, and the enormous cost of either protecting the city or rebuilding it afterward.

The 2015 Paris Accords thus committed parties to limit global average temperature increase to a stable 2.0o C [3.6o F] by 2100, with an aspirational goal of 1.5o C [2.7o F].

Negative emissions

An IPCC Special Report this January explored pathways to the goal. It concluded that the 1.5o C target can probably be met if the world reduces net carbon emissions to zero by 2055 and there after achieves net negative emissions (that is, removes more atmospheric CO2than is emitted.)

What would that mean in practical terms? 

Zero net emissions by 2055 means eliminating nearly all carbon emissions from energy production and transportation, and seriously reducing emissions from food production and buildings.

Over the next 36 years, most of the mines, oil wells, pipelines, and fossil-fueled electric plants would close. Transportation, including autos, railroads, trucks, ships, and airplanes, would be powered by electricity.

Yet utilities, oil companies, and airlines are still investing billions, with government subsidies, in fossil-fuel based infrastructure with over-50-year lifespans. Auto companies are resisting the switch to electric cars, which will force the end of their engine and transmission factories. Electrification of railroads, ships, and airplanes is rarely discussed because it currently seems so impractical.  

Removing CO2

Achieving net negative emissions thereafter means physically removing enough CO2 from the atmosphere to offset both the remaining annual fossil fuel emissions and CO2 from all other sources – cows, rice fields, slash-and-burn agriculture, and melting permafrost. The technology to remove CO2 directly from the atmosphere cost-effectively only exists in the lab.

The IPCC Special Report crucially assumes immediate, substantial reductions in methane (natural gas) emissions.

Methane lasts only about 12 years in the atmosphere, yet its effect during that period is 80-100 times more potent than an equivalent amount of CO2. Its effects are thus far more immediate. Ominously, recent data show methane emissions increasing rapidly since 2007.

Finally, the IPCC Special Report still shows earth’s temperature probably exceeding 1.5°C for most of the period between 2030 and 2060, even if the world pursues the program and meets the 2100 target.

The focus on the 2100 goal downplays the irreversible damage to glaciers, fisheries, and other resources from these higher interim temperatures, strengthening immediate climate change effects.

Inhibiting action 

Why are we still arguing about whether to take immediate action when we should have begun acting over a decade ago?

Several factors inhibit prompt action. Firstly, in the abstract, the media and the public have a hard time imagining that a few degrees of average temperature increase during their entire lives could be a significant threat to themselves or civilization. Only recently have the impacts become evident.

By extension, human instincts are not attuned to the long term, complex realities of compounding effects, ecosystem interdependence, finite natural resources, and population growth. We tend to rely on “muddling through” and remain optimistic that “things will be okay.” 

Global warming is the ultimate “tragedy of the commons” – no individual or even national action is decisive alone. The current US Administration argument against strict auto emission standards is that emitting a little more won’t hurt and emitting even a lot less won’t help.

In addition, carbon emissions are essentially permanent, so each year’s emissions cumulate. Reversing that impact becomes more difficult and urgent with each passing decade. Even small carbon emissions will still contribute to the total warming potential of the atmosphere.

Time horizon

Most people’s time horizon is a lifespan. In 1990, the year 2100 was 110 years away – as far in the future as 1880 was in the past.

Now 2100 is only 80 years away – only as far in the future as 1940 is in the past. Living adults remember WW II; young children expect to see 2100.

The damage from global warming is becoming visible, but the world is still delaying the necessary transformations. Governments aren’t forcing change, and citizens aren’t demanding it.

The coming decade appears to be the last chance to avoid severe, irreversible climate change that will undermine society. The challenge is to shoulder the cost of transforming our economic systems now, in order to save civilization over the years and centuries ahead. 

This Author 

Sam Bleicher is an adjunct professor of law at Georgetown University in Washington, D.C. He was a member and vice chair of the Virginia Air Pollution Control Board from 2014 to 2018. His novel on climate change, The Plot to Cool the Planet, draws on his experience as a senior official in the Ohio Environmental Protection Agency, National Oceanic and Atmospheric Administration, and Department of State.