Understanding Climate Change: What’s In Store

Author Daniel Rirdan breaks down the history and science behind climate dynamics and global warming.
By Daniel Rirdan
August 2012
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From climate change to peak oil, “The Blueprint” by Daniel Rirdan examines the issues that are stressing the world and explains a 15-year plan that could save it.
Cover Courtesy Corinno Press

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The Blueprint (Corinno Press, 2012), by Daniel Rirdan, is a call to arms and an argument for his 15-year, worldwide plan that calls for major changes in the way we impact the planet. In his blueprint, Rirdan offers employable designs that lay down new paths for our economy, technology, industry and politics. The following excerpt on understanding climate change is taken from Chapter 1, “Climate Change: What’s In Store.” 

Climate Dynamics

There were times when tropical forests dominated all continents except Antarctica. There were other times when Earth was almost frozen solid from pole to pole. Life has existed in between those two ends of the climatic spectrum.

What has been controlling the climate of the world is a symphony of myriad notes generated by many instruments.

Beyond the annual cycle of seasons, the shortest notes are the minute fluctuations in solar intensity. Minimal sunspot activity is suspected to be one of the instigators in the climate blip that was the Little Ice Age from about 1300 CE to 1800 CE.

Another short-term player is the sulfur haze vented by the occasional volcanic eruption. The haze deflects sunlight back into space.

When Mount Pinatubo erupted in 1991, the discharge of aerosols reduced the amount of incoming solar radiation. Consequently, the global mean temperature dipped by 0.6°C for a period of two years.

The occasional changes in warm ocean currents can also impact the climate. Their effect ranges from the relatively mild, as in the case of the El Nino phenomenon, to the relatively significant, as when the Atlantic conveyer belt, circulating warm tropical water northward, got stalled about 12,000 years ago. Climatic changes driven by ocean currents are usually regional rather than global in nature.

Superimposed on these rapid climatic fluctuations are the cyclical changes of the Earth’s orbit. These cycles span tens of thousands and hundreds of thousands of years. In some eras, the Earth’s orbit is more elliptical, in others less. In some eras, the Earth’s axis is tilted slightly more toward the sun, in others it is tilted slightly less. The combined effect of these cycles is to redistribute the heat between the two hemispheres and otherwise widen the gulf between summer and winter temperatures. During a given ice age, when the climate is colder to begin with, these orbital oscillations have a pronounced effect: they are the main instigator in getting the Earth in and out of glacial periods within a given ice age.

A bit of an explanation is in order. A glacial period of an ice age is when North America is under a two-mile-thick ice sheet and when ice cover is widespread. The interglacial period of an ice age is what we have had for about the last 10,000 years: permanent ice sheets that are largely constrained to the polar regions.

The two driving engines that get our planet to swing between glacial and interglacial periods are the changes in atmospheric levels of carbon dioxide (CO2) and the amplification effect of the reflective ice cover. (The more widespread the ice cover is, the more sunlight is reflected back with consequently less ground warming.) However, the orbital changes of the planet start these two big engines—the extent of ice coverage and the rates of CO2 emissions—leaning one way at the beginning of a glacial period and the other way at the onset of an interglacial period.

On a scale of tens of millions of years, the thickness of the CO2 blanket changes markedly. The thicker the atmospheric blanket of CO2, the warmer it gets. Over the long run, the foremost mechanism controlling the thickness of the blanket is a ponderous interaction between volcanic activities, which emit CO2, and the weathering process, which locks down the carbon that is in the air.

Over periods of eons, volcanoes belch out CO2. Everything else being equal, the higher the volcanic activity in a given Age, the more CO2 released into the air, and the thicker the greenhouse blanket.

Counteracting this mechanism is the weathering process. Rainfall reacts with the CO2 in the air, creating carbonic acid. The slightly acidic groundwater attacks rocks containing silicate minerals. The ensuing chemical reaction locks into these rocks the carbon contained in the groundwater, taking the carbon out of circulation for a very long time.

The volcano–weathering interplay is probably the greatest climate-engine of them all. When it is all said and done, the ever-shifting balance over millions of years between the rate of weathering and the rate of CO2 emissions from volcanoes and hot springs accounts for the ponderous oscillations of Earth between an icehouse and hothouse climate through the geological epochs. A Hothouse World is predominantly a tropical world. An Icehouse World is what we have had for the past thirty-four million years.

On a longer time scale yet—that of hundreds of millions of years—is the ever-intensifying radiation of the sun. Four and a half billion years ago the sun output was but 70 to 75 percent of its current level.

However, the ever-increasing sun radiation has been compensated by a potent greenhouse blanket in the early period, followed by an overall decrease in greenhouse gas concentrations through the ensuing thousands of millions of years.

Those are the prominent, more obvious instruments controlling climate. There are many ancillary ones, such as the patterns of wind, dust, precipitation, and clouds, which all amplify or mitigate the effects of the key instruments. As the climate changes, so do the patterns of vegetation, soil exposure, and ice coverage—and with them the level of reflectivity of the sun's rays. All of these parameters interact, producing a symphony of dazzling complexity and dynamics.

Then we showed up on the scene.

Global Warming 

The planet’s surface emits the energy from the sun in the form of infrared radiation, or heat. Some of that makes it to outer space, some is absorbed by the so-called greenhouse gases. Those in turn emit some of the heat downward. The net result is augmented warming of the planet surface. Thanks to this blanket of greenhouse gases, Earth does not have an average temperature of −18°C (−.4°F). The resultant 33°C higher average temperature makes life as we know it possible on Earth.

Carbon dioxide is constantly being cycled through the vegetation, ocean surface, and atmosphere. Most of the landmass, and therefore vegetation, is situated in the northern hemisphere. When it is winter in the northern hemisphere, the bulk of the world’s leaves shed and release their CO2, and consequently the atmospheric concentration goes up a bit. In the summer it goes back down.

At the beginning of the current interglacial period, eleven thousand years ago, the CO2 concentration in the air hovered around 259–265 parts per million (ppm). This is pretty much how it stayed until about 3600 BCE, when the carbon dioxide (CO2) levels in the atmosphere started to inch their way up and then plateaued at 276–283 ppm around 480 BCE, where they stayed until the early 1800s.

About that time, we got into the fossil-fuel business and started releasing massive amounts of CO2 into the air. Some of it was picked up by the ocean, some by the land. However, about half of it remained in the air. And we went from an atmospheric concentration of around 283 parts per million (ppm) in 1807 to 391 ppm as of 2011. This CO2 concentration is the highest in the last 800,000 years and potentially for the past few million years.

Carbon dioxide accounts for about 77 percent of the effects of our annual greenhouse gas (GHG) emission. Methane and nitrous oxide account for most of the rest. The main source of anthropogenic, or human-induced, greenhouse gases is the combustion of fossil fuel. We use the resultant heat to generate electricity, to warm indoor spaces, to power our motor vehicles and various industrial processes. Other significant sources of anthropogenic GHG emissions are due to carbon outgassing from the soil, from cement production, and from deforestation.

Secondary sources of anthropogenic GHG emissions include landfills, rice paddies, the production of steel, and the manufacture of petrochemicals. It is unclear whether livestock emissions should also be added to this tally. Our cattle take in CO2 from the air and turn it to the far more potent methane at the back end of the process.

Hence, no cattle, no extra methane. Yet, in some roundabout way, the domestic cattle of today stand in place of the hordes of bison and musk ox of bygone days—which also contributed their share of converting CO2 to methane.

At the end of the day, what matters most is the resultant level of warming from it all. Currently, we are at 0.9°C mean global warming, and there is no doubt that human activities are at the root of it. In fact, if not for the offsetting effects of aerosols and minimal solar activity, the warming would have been greater yet.

Under the business-as-usual, fossil-fuel intensive scenario, in which CO2 concentrations are projected to rise to 872 ppm by the 2090s, an integrated model at the Hadley Centre projects that by that time, the temperature will have increased by 4.4°C to 7.3°C from pre-industrial temperature levels. Under a comparable emission scenario, MIT Integrated Global Systems Model projects between 5.1°C and 6.6°C warming relative to pre-industrial levels by 2100. In accordance, I assume a median figure of 5.5°C global mean temperature increase by the end of the century as a likely outcome under the business-as-usual, fossil-fuel intensive scenario.

As of 2010, the year 2010 was one of the two warmest years on record. In fact, as 2011 came to a close, nine of the ten warmest years in recorded history have been since 2000. During the spring of 2011, fires of epic proportions raged in Texas, which had its driest spring on record. Australia and New Zealand had mega-floods, and the Midwest had record snowfall. This is just the beginning; this is just at 0.9°C warming. These are but first, timid forays of a new weather regimen.

The routine 4°C–7°C oscillations between glacial and interglacial periods take thousands of years to run their course, not one hundred years, as is projected to happen under the current emissions trajectory. Moreover, in the last few million years, the changes have been occurring within the bounds of a certain temperature range. At present, we are already at the warm end of the pendulum. Pushing it 5°C farther out may prove to be outside the operational specs of some of the existing species and ecosystems.

In terms of global mean temperature, we are travelling back in time. In our current trajectory, around mid-century we will have gone back in time to the Pliocene epoch, a few million years back. Toward the end of the century, we are likely to have reached the Mid Miocene Climatic Optimum period, around 15 million years back. And then on to the twenty-second century and further back in time, getting to temperature levels that are likely to have last existed during the Eocene epoch, perhaps around 40 to 50 million years ago—along with ocean acidity not on a comparable time scale.

This is where the similarities may end. It is one thing to have global transitions of climate over millions of years or over many thousands of years, allowing most species to migrate, evolve, or work their way to suitable changing climatic distribution. It is an entirely different ball of wax to turn the dial 5°C‒6°C over a one hundred year period for a planetary ecosystem that is largely bankrupt with only isolated, hemmed-in pockets of intact nature.

This excerpt has been reprinted with permission from The Blueprint: Averting Global Collapse, by Daniel Rirdan, published by Corinno Press, 2012. 

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