By Paul MacRae

In June, a NASA climate study announced that the warm middle Miocene era, about 16 million years ago, had carbon dioxide levels of 400 to 600 parts per million. The coasts of Antarctica were ice-free in summer, with summer temperatures 11° Celsius warmer than today. The study concluded that today’s CO2 level of 393 ppm was the highest, therefore, in millions of years, and could go to Miocene levels by the end of the century[1]. It was implied, although not directly stated, that readers should react with horror.

A UCLA team, writing in Science, had already pushed the Miocene button in 2009, claiming: “The last time carbon dioxide levels were apparently as high as they are today [15 million years ago, again the mid-Miocene]—and were sustained at those levels—global temperatures were 5 to 10 degrees Fahrenheit [2.7-5.5°C] higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland.”[2] Back to the Miocene! Scary!

James Hansen, the alarmist head of NASA’s Goddard Institute for Space Studies (GISS), regularly refers to past eras as a warning of the climate catastrophes that could occur today. For example, in 2011 Hansen warned: “[An increase of] two degrees Celsius is guaranteed disaster…. It is equivalent to the early Pliocene epoch [between 5.5 and 2.5 million years ago] when the sea level was 25m (75 feet) higher.” [4] Back to the early Pliocene! Horror!

And, in testimony to the U.S. government: “The Earth was much warmer than today in the early Cenozoic [which began 65 million years ago]. In fact it was so warm that there were no ice sheets on the planet and sea level was about 75 meters (250 feet) higher.” [5] Heavens! The planet could revert to the age of dinosaurs! (Hansen didn’t mention that sea levels today are 120 metres—almost 400 feet—higher than they were a mere 15,000 years ago, without creating a catastrophe.)

If we don’t curb our carbon-emitting ways, the alarmists warn, we face “increasingly radical temperature changes, a worldwide upsurge in violent weather events, widespread drought, flooding, wildfires, famine, species extinction, rising sea levels, mass migration, and epidemic disease that will leave no country untouched.” [7] The only catastrophe not mentioned here is “acidification” (i.e., a slight decrease in alkalinity) of the oceans.

If a warmer, more CO2-rich world would be hell in the future, it logically must have been hell in the past, too, when global temperatures were much warmer and carbon dioxide levels much higher. How could anything live, for example, in those “acidified” oceans of the Miocene? At least, this is what alarmist climate scientists like Hansen want the public to believe.

An Eocene ‘paradise’

Curiously, while alarmists warn about the horrors of returning to the climate of millions of years ago, paleoclimatologists tell a different story. They more often see our earlier planet as a “paradise,” even “paradise lost.”

In fact, “paradise lost” is the subtitle of a 1994 book on our planet 33 million years ago by veteran paleo-climatologist Donald R. Prothero—The Eocene-Oligocene Transition: Paradise Lost. The Eocene (55-33 million years ago) began what is sometimes called the Golden Age of Mammals. This geological age was at least 10°C warmer than today, free of ice caps, and with CO2 levels, Prothero suggests, of up to 3,000 parts per million, which is almost eight times today’s level of about 400 ppm. Yet Prothero calls the Eocene a “lush, tropical world.”[8]

At the end of the still very warm Oligocene (33-23 mya), Prothero puts CO2 levels at 1,600 ppm, or four times today’s levels.[9] Prothero’s 1994 CO2 estimates may be a high, but no one—not even Hansen—denies that CO2 levels were several times higher than today’s in the Eocene and Oligocene and, indeed, right down to the Miocene (23-5 mya).

For Prothero, the boundary between the Eocene and Oligocene was “paradise lost” because it was then, about 33 million years ago, that the planet began its slide from a “lush, tropical world” into its current ice age conditions (see Figure 1), with glaciations every 85,000 years interspersed with brief, 15,000-year warm interglacials.

Climate over 65 million years

Figure 1: Temperatures over 65 million years. Source: Global Warming Art

In fact, the planet is currently its coldest in almost 300 million years. Yet, for Hansen and others in the alarmist camp, our ice-age world is in danger of getting too hot—maybe even as hot as the Pliocene, or the Miocene, or the Oligocene, or even, heaven forbid, the Eocene.

Many other writers on paleoclimate also use the term “paradise” to describe climate in the distant past. For example, in a history of evolution for younger readers, science writer Sara Stein paints the Eocene of 50 million years ago as follows:

The world that all the little brown furry things [mammals] inherited from the dinosaurs was paradise. [emphasis added] The climate was so mild that redwoods, unable now to live much further north than California’s pleasant coast, grew in Alaska, Greenland, Sweden, and Siberia. There was no ice in the Arctic. Palm trees grew as far north as 50 degrees latitude, roughly the boundary between the United States and Canada. Below that subtropical zone—that was similar to Florida’s landscape today—was a broad band of tropical rain forest.”[10]

Sounds grim, doesn’t it?

One of the most prominent climate alarmists, Tim Flannery, also uses the “p” word when he describes Eocene North America in his very readable The Eternal Frontier, on the geological and biological history of North America. Flannery writes:

When Earth is warm (in greenhouse mode)—as it was around 50 million years ago—North America is a verdant and productive land. [emphasis added] Almost all of its 24 million square kilometers, from Ellesmere Island in the north to Panama in the south, is covered in luxuriant vegetation.[11]

Flannery titled the section of the book that deals with the “verdant and productive” Eocene as: “In Which America Becomes a Tropical Paradise.” Yet this was a time, it should be remembered, when temperatures and CO2 levels were much higher than today’s. Unfortunately, trapped in his alarmism, Flannery doesn’t see the irony.

British paleontologist Richard Fortey describes the landscape of Australia 20-35 million years ago, during the Oligocene and Miocene, as being “as rich as Amazonia, green and moist, with trees and ferns in profusion.”[12]  Today much of Australia, an area the size of the continental United States, is desert and bush and supports only 22 million people compared to 300 million in the U.S.

As recently as 125,000 years ago, the peak of the last interglacial, our planet was 3-5°C warmer than today at the poles according to the Intergovernmental Panel on Climate Change (IPCC) itself, with sea levels 4-6 metres (12-20 feet) higher than today’s interglacial so far.[13] Even Britain was semi-tropical, with hippopotami gamboling in the Thames, apparently untroubled by extreme weather events, extreme droughts, extreme flooding, etc.

A mere 8,000 years ago, during the Holocene Optimum period that was at least 1°C warmer than today, much of the Sahara Desert was green, as were many other regions that today are desert.[14]  Why? Because warmer temperatures mean less polar ice, making more water available for precipitation, and therefore promoting a greener planet.

So, millions of years ago, during geological eras much warmer than today, with much higher levels of carbon dioxide, the planet faced the same environmental hazards we face today—volcanoes, earthquakes, tsunamis and the like. But it was not plagued by the extreme weather events, extreme droughts, extreme flooding, mass extinctions, or even the ocean “acidification” claimed by climate alarmists for the world of the future.

Sea level ‘disaster’?

On only one point have the alarmists got it right: during these warmer times of the geological past sea levels were higher, sometimes many metres higher—a point Hansen mentions again and again in his presentations.

For example, Hansen notes that while only two per cent of the Earth’s land surface is within 10 metres of sea level, this two per cent also has 10 per cent (more than 630 million) of the world’s population. Hansen says a five-metre (15 foot) rise would, without costly dikes or other measures, inundate many large cities, including New York, London, Shanghai and Tokyo. This sea level increase, he concludes, would be “disastrous.”[15] Hansen even seriously predicts five metres (15 feet) of sea-level rise by the end of the 21st century under a Business As Usual carbon scenario.[16]

However, most climate scientists—even alarmist scientists—know that Hansen’s predictions are hallucinations and accept that a sea level rise of this magnitude could only take place over centuries and millennia, just as sea levels have risen 120 metres (400 feet) over the past 15,000 years.

For example, in 2006 the Sierra Club released a map of Victoria, British Columbia, flooded by a sea-level rise of from six to 25 metres (see Figure 2). The Sierra Club predicted that if we did nothing about carbon emissions, flooding of this magnitude could occur “in the lifetime of our grandchildren,” that is, within the century.[17]

Victoria under water

Figure 2: Victoria, B.C., under water ‘in the lifetime of our grandchildren.’ Source: Sierra Club.

Even University of Victoria climatologist Andrew Weaver, an arch-alarmist, was moved to protest against this barrage of exaggeration and misinformation, writing to the Victoria Times Colonist letters page: “The science suggests serious societal consequences of global warming in the short term, while the changes in sea level that the Sierra Club tout happen over thousands of years. [emphasis added] This clumsy story just makes it easy for the deniers to claim there is no problem.”[18]

Even the ultra-alarmist site de Smog Blog joined the chorus against the Sierra Club’s absurd apocalyptism with an article entitled “Sierra Club drowns in own climate catastrope” (the de Smog headline writer apparently could not spell “catastrophe”).

In other words, in the real world (as opposed to Hansen’s world), sea-level rise of any magnitude will take centuries and even millennia. The current rate of sea-level increase is just over 2 mm a year, or about 20 cm per century. At this rate—and at the moment the rate shows no signs of increasing—sea levels would take 2,500 years to reach Hansen’s five metres. Based on several interglacials over the past 600,000 years, which at their peak had sea levels several metres higher than today’s levels according to the IPCC, the seas would rise five metres or more even if human beings didn’t emit carbon.

Coping with sea-level rise

Can humanity cope with rising sea levels, whatever those levels may be? If climate alarmists don’t succeed in crippling our carbon-based economy, even the IPCC predicts that both developed and developing countries will have all the prosperity they need to cope with rising sea levels, be it seawalls, landfill, or relocations to desert and polar areas now fit for settlement due to warmer temperatures and greater precipitation.

Figure 3 shows GDP per capita for four of the IPCC’s climate scenarios, from Business As Usual to anti-carbon, between 1990 and 2100. In all four scenarios, humanity becomes better off, but humanity is best off in the red-line scenario, which is basically Business As Usual.

GDP increase by 2100

Figure 3: GDP per capita 1990-2100. The red line represents the IPCC scenario with the least attempt to stop climate change, which makes humanity the richest. Source: Arnell et al., 2004. [19]

In the BAU scenario, the world’s per capita GDP will rise from $5,000 a year in 1990 to $70,000 a year in 2100, based on 1990 dollars. In other words, if we do nothing at all to try to stop global warming, by 2100 even poor countries will have the resources they need to adapt to climate change, whether warmer or cooler.

And, again, a warmer, wetter planet would “green” many of the world’s desert regions, including the Sahara and Australia, just as warming did in ages past. Meanwhile, thousands of square miles of land currently under ice or Arctic scrub would be open to settlement.

A wetter, greener world

And this still doesn’t take into account the positive effect of higher levels of CO2 in fertilizing plants. Physicist and biologist Sherwood B. Idso, who has specialized in charting the relationship between CO2 and plants, notes:

A simple 330 to 660 ppm doubling of the air’s CO2 content will raise the productivity of all plants, in the mean, by about one-third. … As atmospheric CO2 concentrations more than double, plant water-use efficiencies more than double, with significant improvements occurring all the way out to CO2 concentrations of a thousand ppm or more.

Think of what such a biological transformation will mean to the world of the future. Grasslands will flourish where deserts now lie barren. Shrubs will grow where only grasses grew before. And forests will make a dramatic comeback to reclaim many areas presently sustaining only brush and scattered shrubs. [20]

Sound utopian? Even the IPCC acknowledges that doubled CO2 levels can produce increases of up to 33 per cent in plant growth, while also making plants more drought resistant.[21]

Millions of years ago our planet was much warmer and wetter than today, with much higher levels of CO2. Alarmists like Hansen say a return to those temperatures and CO2 levels would be catastrophic. Yet the planet in earlier geological ages is almost always described as a tropical paradise, not a blasted, carbon-choked hell. Sea levels were higher, but a prosperous humanity can cope with higher sea levels.

However, the huge Antarctic ice cap—the “deep freeze” in our planet’s basement—didn’t exist in the Eocene or Oligocene. So even if the catastrophic anthropogenic warming hypothesis is valid—that’s doubtful but if—it’s unlikely our planet will go back to Eocene or Oligocene warmth.

But if, as alarmists warn, we return to the Pliocene, or even the Miocene, would that be paradise lost? Or paradise regained?


[1] “Study finds ancient warming greened Antarctica.” NASA website, June 17, 2012.

[2] “Last Time Carbon Dioxide Levels Were This High: 15 Million Years Ago, Scientists Report,” Science Daily, Oct. 8, 2009.

[3] James Hansen, “G-8 Failure Reflects U.S. Failure on Climate Change.” Huffington Post, July 9, 2009.

[4] Hansen, Address to American Geophysical Union, December 2011.

[5] Hansen, “Statement of Witness James E. Hansen.” No date given.

[6] Hansen, Storms of My Grandchildren: The Truth About the Coming Climate Catastrophe and Our Last Chance to Save Humanity. New York: Bloomsbury, 2009, p. 265.

[7] Nuclear lobbyist John Ritch. Quoted in Tom Zoellner, “Nuclear power gets its swagger back.” Globe and Mail, March 14, 2009, p. F5.

[8] Donald R. Prothero, Eocene-Oligocene Transition: Paradise Lost. New York: Columbia Univ. Press, 1994, p. 35.

[9] Prothero, pp. 22, 238

[10] Sara Stein, The Evolution Book. New York: Workman Publishing, 1986, pp. 245-246.

[11] Tim Flannery, The Eternal Frontier: An Ecological History of North America and its Peoples. London: Vintage, 2002, p. 84.

[12] Richard Fortey, Life: A Natural History of the First Four Billion Years of Life on Earth. New York: Alfred A. Knopf, 1998, p. 270.

[13] IPCC 2007 Summary for Policymakers, p. 9.

[14] See Wikipedia “Holocene climatic optimum” and “Green Sahara” for details.

[15] Hansen, “Climate Catastrophe.” New Scientist, July 28, 2007.

[16] Hansen and Makiko Sato, “Paleoclimate Implications for Human-Made Climate Change,” 2011.

[17] “Rising ocean would flood much of Greater Victoria.” Victoria Times Colonist, Dec. 6, 2006.

[18] Andrew Weaver, “Scary story sets back understanding.” Letter, Times Colonist, Dec. 8, 2006.

[19] Nigel Arnell, et al., “Climate and socio-economic scenarios for global-scale climate change impacts assessments: Characterising the SRES storylines.” Global Environmental Change, 14 (2004), p. 9. See also Indur Goklany, The Improving State of the World. Washington, Cato Institute, 2007, pp. 303-309.

[20] Sherwood B. Idso, “Carbon dioxide and global change.” Rational Readings on Environmental Concerns, Jay H. Lehr, ed. New York: Van Nostrand Reinhold 1992, p. 422.

[21] IPCC 2001, Chapter 3, Section, p. 195. See also IPCC 2007, Working Group III, Chapter 3, Section, “Land use change and land use management.”