Ronald Reagan said, “Trees cause more pollution than automobiles do,” ignoring trees’ conversion of CO2

September 7, 2014

Climate Change

Trees cause more pollution than automobiles do.

“The American Petroleum Institute filed suit against the EPA [and] charged that the agency was suppressing a scientific study for fear it might be misinterpreted… The suppressed study reveals that 80 percent of air pollution comes not from chimneys and auto exhaust pipes, but from plants and trees.

– Former Republican President Ronald Reagan in 1981 and 1979 respectively

There is no peer-reviewed study that concludes that trees cause 80% of pollution, or that they cause more pollution than cars

Reagan received criticism from this, especially from democrats and the scientific community.

To be fair, some trees are known to release terpenes and isoprenes, which are linked to photochemical smog and ground level ozone pollution. A Yale study also showed that some trees infected with fungi can release methane. But that methane is only 18% of the CO2 removed from the atmosphere by trees. 

Cars contribute a lot of other things to the atmosphere, including:

  • particulate matter (soot, metals)
  • hydrocarbons (smog)
  • nitrogen oxides (lung irritants)
  • carbon monoxide (can cause suffocation)
  • sulfur dioxide (cause of acid rain),
  • and greenhouse gases such as carbon dioxide. 

In other words, trees help the atmosphere. They have a net positive effect. Cars do not have this redeeming quality. In 1980, around the time Reagan made this statement, according to the EPA, highway vehicle emissions looked like this:

  • carbon monoxide:    143,827,000 tons
  • nitrogen oxides :        11,493,000 tons
  • sulfur dioxide:                 394,000 tons

While Reagan’s statement is worth further investigation, it is misleading and irresponsible, and convinces people that we do not have to respect our environment. 

, , , , , , , , , , , , , , , , , , , , , , , , ,

About jslachman381

I'm a Yale graduate who majored in History of Science, Medicine, and Public Health.

View all posts by jslachman381


Subscribe to our RSS feed and social profiles to receive updates.

2 Comments on “Ronald Reagan said, “Trees cause more pollution than automobiles do,” ignoring trees’ conversion of CO2”

  1. Brian Says:

    Cars have no net positive effect? Then how would people get around without cars? What would the net effect when you calculate that without cars, people wouldn’t turn into stationary stone monoliths, but would likely get around by other means, like horses. Do you care to calculate the total energy cost of a horse? How much irrigated land dedicated to growing grass for hay is needed to maintain it, even when it isn’t in use? How much water it requires?

    Don’t just do some of the math. Do ALL the math.



    • jslachman381 Says:

      From the author: Brian, I appreciate your comment, but you’re misunderstanding the point. You’re talking about a positive societal effect, which can’t be easily accounted for in calculations. What this post is discussing is the overall effects of car emissions versus tree emissions. Car emissions have an overall negative effect on the environment, whereas trees overall have a positive effect when discussing their contributions to the greenhouse effect.

      The overall point of the whole post is to point out that President Reagan spoke irresponsibly about the effects of cars versus trees on the environment, and that politicians should take greater care when disseminating scientific information to the public.

      I hope this satisfies your concerns with the writing.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: