Carbon Offsets

Carbon Offsets


Executive Summary

CO2 emissions is one of the largest drivers of Climate Change..  The emissions from Americans are nearly TEN TIMES the global target required to slow or stop climate change1.  To avoid catastrophic climate change, it is imperative that we take actions as individuals and as a congregation to reduce our CO2 emissions and carbon footprint, especially in the areas of sustainable energy, transportation, food and overall consumption.

In addition to personally reducing CO2 emissions, including the purchase of carbon offsets can also help to reduce emissions worldwide, as long as the offsets are legitimate and in addition to our actions.

One good site which lists carbon offset standards and then links to the organizations which meet those standards is:

The highest standard of legitimacy, is the “Gold Standard CER”.  These suppliers generally charge $20-$30/T (ton of CO2 offset).  Examples:  Atmosfair, ClimateFriendly, MyClimate and Sterling Planet.

There are multiple companies and non-profits which are not Gold Standard, but appear legitimate, cost less and have other attractive features.  In the attached paper, I list my opinions on the following suppliers:  Terrapass,, NativeEnergy, Nature Conservancy, United Airlines, and Cool Effect.  These suppliers charge $5-$20/T.

In summary, there are multiple legitimate carbon offset suppliers, and carbon offsetting can be very cost effective supplement to our actions and advocacy to reduce CO2 emissions.

If you want more details on carbon offsets, refer to “Carbon Offsets – An Overview for Scientific Societies”, by University of Pennsylvania Professor Benjamin Pierce. 2  

The following pages summarize some of the key points from the Pierce paper, and then provides my opinions of some pros and cons about purchasing offsets from the 10 suppliers I surveyed.









Buying Carbon Offsets: Overview

We know that we all have incredibly large carbon footprints:  On average, our emissions are FIVE TIMES higher than the world’s average, and TEN TIMES higher than the global target.1

There are many actions that we can and should take, as individuals, and as a congregation.  Actions and advocacy for:

  • Switching to renewable energy (solar or wind),
  • Using more sustainable travel (hybrids, electric and fewer flights),
  • Eating more sustainably (mostly plant based, but especially less beef and lamb) and
  • Generally consuming less and recycling more.

However, even after the best of our efforts, it is unlikely that we will decrease our individual consumption and footprints by 80% to 90% needed to reach the global targets.

One way to close the gap quickly and cost effectively is carbon offsets.  Although there is some criticism that use of carbon offsets is a crutch, and can delay the other actions which should be taken, I have reached the conclusion that legitimate offsets are a good adjunct to an action and advocacy plan.  This conclusion was also reached in the paper “Carbon Offsets – An Overview for Scientific Societies”, by University of Pennsylvania Professor Benjamin Pierce. The entire paper is an excellent reference.

If you decide you want to use carbon offsets, then the first question is which ones are “legitimate”?  Additional key questions are which ones are sustainable and cost effective?  It is also helpful if they can be easily purchased, and have a user-friendly certificate verifying what you have purchased.

This paper attempts to briefly answer those questions, and includes multiple references to the Pierce paper.

What Carbon Offsets are available?

There are dozens if not hundreds of carbon offsets from NGOs, for profit companies, web sites and scams.

Which Carbon Offsets are legitimate?

There are four criteria (including permanence and verification), and at least 27 standards commonly exist to evaluate carbon offsets.3    A supplier certified by one of these standards is viable.

One good site which lists 27 different standards (eg, Gold Standard CER), and then links to the organizations which meet those standards is:

Gold Standard CER suppliers in my survey were Atmosfair, ClimateFriendly, MyClimate, and SterlingPlanet.   Terrapass meets the VCU (VCS), CFI (CCX), and CCAR standards.

In my survey of potential suppliers, I took the leap of faith that organizations that had been selected by large corporations were likely to be legitimate, because corporations have the wherewithal to research their suppliers and their potential PR nightmare if their carbon offsets are fraudulent.  Included in my survey were:  Nature Conservancy, United Airlines, and Native Energy.

I also included a few which “appeared” legitimate, had other articles referencing them positively and for which my quick internet scan found no claims of fraudulence.  They are probably OK, but I cannot vouch for them, but I like their good carbon footprint maps.  Included in my survey were CarbonFootprint and CoolEffect.

Which are sustainable?

The carbon offset evaluations use the term “permanence”.  So, meeting many of the standards, such as the Gold Standard CER, requires permanence.

The 4 criteria in the standards are Additionality, Permanence, Leakage and Verification.  See Pierce for more details.

Many of the programs allow you to select a specific project type, so you can better choose one which seems more sustainable.

Interestingly, several articles I read suggested that my personal favorite, Tree Planting, does not generally meet the permanence criterion, unless the program includes the care and watering for decades, and a commitment not to chop down those trees. Tree Planting is also at high risk for lack of additionality.   Conversely, the articles suggested that cookstove and bio-gas projects generally score higher in permanence.

Which are cost effective?

The short answer is:  All of them (all the legitimate ones).  The bulk price appears to range from $1 to $10 per ton.  The retail price ranges from $5 to $50.  Many are clustered around $15, and the Gold Standard programs are usually $20-30.  So, for as little as $100 per person per year, you can offset several TONS of CO2 emissions.

Here are representative the prices per ton for selected projects from the sites I investigated:

Cool Effect: $5.27 to $13.18

TerraPass:  $9.98

Carbonfootprint:  $12.49

United Airlines: $12.50

Nature Conservancy: $15.00

Native Energy:  $15.50

Sterling Planet (Gold Standard): $25

Atmosfair (Gold Standard):  $26.00

MyClimate (Gold Standard): $30

Climate Friendly (Gold Standard):  I could not navigate the site

Which are easy to purchase?

Nearly all of them, although I had to buy Atmosfair offsets in euros, and Climate Friendly which I could not navigate.

Which have user-friendly certificates?

This is a personal preference.  I compared certificates from 7 suppliers that I purchased offsets from.

In my opinion, the best ones included both the project name and the tons of CO2 offset:  United Airlines,, CoolEffect.

The next best included only the amount of the CO2 offset (Terrapass), or only the project (Atmosfair and CoolEffect air travel).

The worst didn’t send a certificate, so I had to cut and paste their Thank You email, which only included a dollar amount:  Nature Conservancy.


There are a multitude of carbon offset suppliers.  Some are fraudulent, many are legitimate, and some are even certified.  Best case is to use Gold Standard suppliers.

Since it is nearly impossible to reach the 2T per person goal CO2 of emissions, I recommend supplementing our actions and advocacy plans with the purchase of carbon offsets from a legitimate supplier of your choice.

02/2019 For questions, comments or corrections, please contact Ken Crandell.










1 The US average is 18T per person (18 tons of CO2 emission per person per year).  Howard County is one of the 10 richest counties in the US, so our average footprint is even higher (probably well above 20T).  The current worldwide average is 4 tons and the target is 2 tons.  So, on average, Howard Countians’ carbon footprints are FIVE TIMES above the worldwide average  (20T/4T=5) and TEN TIMES above the worldwide target (20T/2T=10).

If you want to estimate your own carbon footprint there are many models available for free on the internet, such as, MyClimate and the EPA web sites.


2    “Carbon Offsets An Overview for Scientific Societies” by Richard Kim and Benjamin C. Pierce Version 1.2 June 24, 2018


3  From Pierce’s paper:  “Four basic criteria are commonly used to evaluate carbon offsets (additionality, permanence, absence of leakage, and verification), and several different standards (such as the Verified Carbon Standard, the Gold Standard, and the Clean Development Mechanism) are used by vendors (such as atmosfair and Cool Effect) to certify that particular carbon-offset projects satisfy these criteria to an acceptable degree. Types of offsetting projects range from renewable energy development and energy efficiency improvements to reducing carbon emissions from industrial and agricultural processes and to biosequestration (e.g., planting trees), to deploying technologies for carbon capture and storage.”




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