Lets get some scope on this issue. Carbon dioxide is identified as a greenhouse gas produced by nature and by humans. Some of the natural sources of CO2 are volcanos, forests and ocean waters (surprise there). Human sources include car exhaust emissions, power plant emissions and so on.

At this point, I need to clarify one thing: greenhouse gas versus carbon dioxide. Greenhouse gases represent all of the atmospheric components that can retain the heat from the sun and raise the Earths average temperature. According to NASA, its estimated that water vapor accounts for about 50 percent of Earths greenhouse effect; clouds come in at 25 percent; carbon dioxide follows at 20 percent; and the minor greenhouse gases, including exhaust emissions and aerosols, are the remaining 5 percent. How can lubricants add to the story?

An article by Peter Ferrara published in Forbes, citing The Economist, noted that mankind added 100 billion metric tons of carbon dioxide to the atmosphere between 2000 and 2010. Sounds like a big number, and it is. However, to put this in perspective, the Earths atmosphere comes in at a whopping 10 quadrillion metric tons! That means the additional CO2 put into the atmosphere is a mere 10 parts per million. Just recently, it was announced that the level of CO2 in the atmosphere had reached 400 ppm.

Of course, you should know that CO2 is extracted from the atmosphere by photosynthesis. Plants consume large quantities. For example, in one year, an acre of forest can absorb twice the CO2 produced by the average cars annual mileage. Oceans absorb over 700 billion tons of it annually.

Getting back to Castrol, the manufacturer uses a five-step process to determine its targets for carbon neutral status. First, it tries to quantify the amount of CO2 to neutralize. In this case, it looks at greenhouse gas emissions that are produced. Second, the company identifies areas where it can reduce or replace CO2 emissions. Reducing is pretty much self-explanatory, but replacing is a bit more subtle and could mean replacing products, processes or services with lower-carbon-emitting alternatives.

Third, Castrol utilizes carbon credits to cover the remaining emissions. In theory, for every ton of CO2 emitted, a company can buy certificates attesting that the same amount of greenhouse gas was removed from the atmosphere through renewable energy projects such as tree planting. Emissions reduction schemes, such as the one known as cap-and-trade from the Chicago Climate Exchange, work as follows: If a companys carbon emissions fall below a set allowance, that company can sell the difference-in the form of credits-to other companies that exceed their limits.

The fourth step is to docu­ment the amount of CO2 saved against that which is used to prove Castrols neutrality claim. A compliance document is produced by countries that signed the Paris climate accord, while in the United States, which did not sign the environmental agreement, corporate participation is voluntary. Castrol publicly announces all of the documentation to support its claims.

As an example of Castrols efforts to reduce greenhouse gas emissions, the company assisted Meridian Magnesium Products in Eaton Rapids, Michigan, in lowering its carbon emissions per ton of metal produced by 72 percent. Meridian had used the industry standard sulfur hexafluoride (SF6) as cover gas in its operations. Cover gas blankets the reactive magnesium metal for safety. SF6 is inexpensive, non-reactive with magnesium, non-toxic and relatively easy to use. However, it is also an incredibly powerful greenhouse gas that has a global warming impact about 23,900 times stronger than CO2.

However, in a pioneering move, Meridian began using 3Ms Novec 612 to replace SF6 in its operations. This choice of cover gas saved over 2,000 tons of CO2 over a ten-year period. How did Castrol participate? It bought carbon credits to aid Meridian. I think you get the picture: Find ways to reduce emissions, use offsets to fill in the gaps and claim the benefits.

Were coming out of the woods and heading for a clearing. ACEA (the European Automobile Manufacturers Association) published data that says the CO2 emissions of European cars has dropped by nearly half since 1995. It goes on to report that nitrous oxide and particulates have dropped over 90 percent in the same timeframe due to vehicle design changes.

It should be obvious that fuel economy is one of the major ways to claim reductions in greenhouse gas emissions. As you know, the efforts by the automotive industry have led to lighter vehicles, vastly improved exhaust systems, more efficient engines and transmissions, computer-controlled combustion and, more recently, new engine designs such as turbocharged direct-injection engines.

The engine oil marketplace has done its share, as well. Working in concert (and sometimes struggling to keep up) with engine builders, many improvements in engine oil chemistry and additive formulations have been accomplished over the past 40 years. The past 10 to 15 years have been especially active.

So lets go back to the forest and look at some of the bigger trees. Phosphorus content doesnt get as much attention as other factors, but think of this: If phosphorus hadnt been lowered from its 1980 level of approximately 0.11 to 0.12 percent by weight to its current 0.06 to 0.08 percent level, the catalytic converters in modern vehicles would have been in real trouble. Phosphorus, which is normally supplied by zinc dialkyl­dithiophosphate, can poison the catalyst or form zinc pyrophosphate, a glass-like material that can coat the catalyst and deactivate it. Original equipment manufacturers made the change to roller followers on the cam, which dont need as much antiwear additives as the old flat tappet sliding followers, and the oil and additive industries followed.

A favorite of mine is viscosity reduction, which lowered internal engine friction to allow better fuel economy. From SAE 10W-40 engine oils in 1975 to todays SAE 0W-20 and lower, fuel economy has improved by upwards of 3 to 4 percent. Add friction modifiers to that, and you can easily come up with reductions from the SAE 10W-40 to today that probably exceed 5 percent. Dont hold me to that number, since I dont think Ive seen an exact comparison between an API SE SAE 10W-40 product and an API SN Plus-Resource Conserving SAE 0W-20. There are undoubtedly bench test results that could be applied to this question.

Its not just fuel economy that has improved but volatility, as well, and for that we have to look at base oils. Forty years ago, the first API Group II base stocks were just beginning to appear. Sunocos Puerto Rico refinery at Yabucoa was producing hydro­treated base stocks in 1975. These were just over the line into the Group II category and actually made for some interesting formulation adjustments. Shortly thereafter, Chevrons Richmond, California, refinery came on stream with what is probably the standard for Group II. Since then, numerous other sources have appeared.

In addition, Group III has become a force in the marketplace. Originally, Group III was not so much a primary base stock but rather used for very specialized products and as a volatility adjuster. However, it has found a foothold as a synthetic (courtesy of the 1999 Mobil/Castrol decision), and by the time you get to SAE 0W-20 with the required performance, Group III becomes an integral part of the equation.

Finally, my all-time favorite, computer-controlled engine operations have gone from not even there to the most important part of the engines fuel delivery and timing system. I read somewhere that the great inventions of all time are the stirrup, which allowed a warrior to effectively fight on horseback; gunpowder (no further explanation needed); and the microchip, which allowed the computer to escape the vacuum tube. The first chip could hold about 100 bytes of information and was the size of an LP record (for any vinyl enthusiasts reading). By 1993, Swedish car manufacturer Saab Automobile announced that their computer-controlled ignition Lambda emissions system had more computing power than the Apollo moon mission vehicles. Look where were at now!

As I look back over this literary ramble, weve come a long way from the 1970s when horsepower and cubic inches were the name of the game. Now its fuel economy, emissions controls and greenhouse gas reduction. The future is gonna be busy!

Industry consultant Steve Swedberg has over 40 years experience in lubricants, most notably with Pennzoil and Chevron Oronite. He is a longtime member of the American Chemical Society, ASTM International and SAE International, where he was chairman of Technical Committee 1 on automotive engine oils. He can be reached at steveswedberg@cox.net.