Fossil Fuels and Climate Change

I have never seen climate change discussed without the participants accusing someone either of lying or of destroying the planet.  Everyone gets emotional about climate change, even professionals who have a responsibility to remain impartial.  I think the reason for this is that the topic threatens so many people, because invariably the topic turns to changes that might be necessary in lifestyle, livelihood, and behavior.  Most people don't like change and view being asked to change anything as threatening.  People get emotional when they feel threatened; sometimes they get irrational.

But in the energy world today, addressing climate change is fair game.

Some Facts

Let's start by looking at some facts:

• Burning hydrocarbons releases carbon dioxide (CO2) and water vapor.  (Depending upon the combustion conditions and impurities in the fuels, it can also release other chemicals, but let's not complicate things with that right now.)

• The earth has natural processes for balancing the amount of CO2 in the atmosphere.  These processes transfer billions of tonnes of CO2 between natural sources and sinks such as the oceans, the atmosphere, and the biosphere.

• Society has been burning hydrocarbons on an industrial scale since the beginning of the Industrial Revolution, which started in the 1750s.

• The amount of CO2 produced by burning fossil fuels each year is small compared with the total amount of CO2 balanced by the earth's natural sources and sinks each year.

• Increased concentrations of CO2 in the earth's atmosphere work like a greenhouse, trapping heat that would otherwise be dispersed into space.  (No one disputes this anymore.)  If atmospheric CO2 concentrations increase enough, it stands to reason that temperatures throughout the world will increase too.

The Source of Doubts

In terms of the earth's history, burning fossil fuels on a massive scale and releasing the produced CO2 into the atmosphere is new.  It's only been about 250 years since the start of the Industrial Revolution, but the earth is millions of years old.  Since the Industrial Revolution, society's development has been driven by continually expanding heavy industry and more mechanical transportation, and CO2 emissions have increased steadily every year.

It's absolutely true that the earth has natural processes for balancing CO2 between the atmosphere, oceans, and biosphere.  What's not clear is how delicate these processes are.  It's a real question whether the earth's natural CO2-balancing processes can accommodate the sustained, steadily-increasing CO2 volumes generated by manmade industry and transportation.  If they can, then in the long-term there will be no problem; but if they can't, then the consequences are a wildcard.

This question of how much additional atmospheric CO2 the earth can tolerate is the root of the climate change debate and what actions should be taken, if any. 

How Much CO2 Are We Talking About?

Here's how much CO2 has been released from burning fossil fuels in the roughly 250 years since the Industrial Revolution began:

            1.396 trillion tonnes
                     (Source of data:  Carbon Dioxide Information Analysis Center, www.cdiac.oml.gov)

Here's a way to put this into perspective.  If all this CO2 was collected as a single cube of dry ice, the cube would be 6 miles (9.6 km) on each side.  That's a cube 6 miles east-west, 6 miles north-south, and 6 miles straight up.  And every year the cube grows bigger.

The debate continues over whose fault this is and whether it's a real problem or a just a red herring created by special interest groups with their own agendas.  And while the debate continues, the accusations and hyperbole will undoubtedly continue too.

But I look at this this way:  we've put the equivalent of a 6-mile CO2 cube into the atmosphere.  Does it take a huge stretch of the imagination to think this might have affected something?

Details of calculations:

From 1751 - 2008:  346,758E6 tonnes of carbon emitted

From that data, the average rate of emissions from 2005-2008 = 8432E6 tonnes of carbon/year

Total carbon emitted from 1751-2012 = [346,758 + 4*(8432)]E6 tonnes of C

multiple C tonnes by 3.67 to get CO2 tonnes  (44 gCO2/12gC)(1 mole CO2)/(1moleC) *(g C)

Density of solid CO2 = 1562 kg/m3  --> cube of 9.6 km per side