Eco-Justice Ministries  

Eco-Justice Notes
The E-mail Commentary from Eco-Justice Ministries

Rate of Change
distributed 5/30/08 - ©2008

If I'm driving down the highway at 55 miles per hour, and see a red light, I may start slowing down a few blocks in advance. That's a reasonable way to come to a stop.

If I'm cruising along at highway speeds, and slam a bridge abutment, my car will come to a much more sudden stop. Instead of using 1/6 of a mile to come to a halt, all of that deceleration would happen in about 6 feet.

A gradual stop using the brakes is routine and uneventful. The sudden stop from hitting an immovable object may well be fatal. In both cases, the car goes from 55 to zero, but in one case the process takes several seconds. In the other case, it happens almost instantly.

I use that illustration fairly often to show the importance of the rate of change. How quickly or gradually a change happens makes a big difference. That's a practical consideration on the highway, of course. It is also a major consideration in the crisis of global warming.

Almost everybody who has studied the matter now agrees: human influences, primarily from the burning of fossil fuels, are changing the Earth's climate. Rising concentrations of "greenhouse gasses" such as carbon dioxide are leading to rising average temperatures across the planet.

Those who downplay the significance of global climate change point out that the Earth's climate has always had large fluctuations. There have been ice ages, and very warm periods. They're right about that.

Chart of CO2 levels What is remarkable in the case of human-caused climate change, though, is the rate of the change. A graph plotting atmospheric carbon dioxide levels over the last 160,000 years shows lots of peaks and valleys, with values ranging from 180 to 300 parts per million. At the right hand edge of the graph, where history becomes current events, the line goes vertical and climbs toward 400 ppm. The jagged line of peaks and valleys becomes a cliff.

In 1958 the global level of carbon dioxide was already high at 314 parts per million. Now it is well over 380 ppm. If the industrial world keeps burning coal and oil the way we have been, predictions for the year 2100 put CO2 levels between 650 and 970 ppm.

There always have been fluctuations in carbon dioxide levels, and average global temperatures always have moved up and down in tandem with CO2. The problem today is that the Earth's biosphere is slamming into the vertical cliff of an abrupt change. And just like driving your car into a cliff, such a sudden change may be fatal.

When climate shifts by a couple of degrees across several thousand years, it is possible for species to adapt. Plants and animals can spread into different areas where they can thrive. Predator and prey relationships can shift when change is gradual. But when that change is abrupt, there's no opportunity to adapt.

The sugar maples of New England can't pick themselves up and move several hundred miles north in just a couple of decades. The human communities that depend on those trees for tourism and syrup production will be in big trouble when the trees start to die.

Glaciers that have provided a stable water supply -- in the Himalayas, the Andes, the Alps and the Rockies -- are melting abruptly. Communities that depend on the glacier's year-round water -- human and other species alike -- will suddenly find dry riverbeds during the seasons of greatest need.

Those sorts of changes in climate are stressful when they happen gradually. They are catastrophic when they happen suddenly. The astounding rate of change in temperature is the reason why global warming is such an urgent concern.

+     +     +     +     +

The US government's long-standing pattern of inaction on global warming is starting to change. ("Better late than never", is true.) Next week, when the US Senate comes back from their Memorial Day break, they are scheduled to debate a piece of legislation called the "Climate Security Act of 2008" (S. 3036).

The bill, co-sponsored by Senators Lieberman (I-CT) and Warner (R-VA) is an important starting point in reducing this country's greenhouse gas emissions. Senators of all parties need to hear that we're glad this bill has made it to the floor. But they also need to hear that the proposed Climate Security Act is just a starting point. It does not go far enough, or fast enough.

Urge your two Senators to strengthen the act. It should include measurable steps to:

  1. reduce the US's carbon emissions 15-20 percent by 2020, and 80 percent by 2050;
  2. shield vulnerable populations from the disproportionate dangers they will be exposed to as the planet warms; and
  3. limit the financial burdens placed on those living in poverty and low-income families by spreading costs of changing our energy habits fairly and sustainably.

The rate of change in global carbon dioxide levels, and in climate impacts, is continuing at an unprecedented and reckless pace. We don't have the luxury of gradual adjustments. Indeed, some climate experts are saying that we've already passed the maximum sustainable CO2 level of 350 ppm. We need strong and rapid action.

Our friends and colleagues with the Eco-Justice Program of the National Council of Churches have organized political advocacy tools that will help you send emails to your Senators. Even better (or in addition), make a short phone call to each of your Senator's offices, and tell them to vote for amendments to the Climate Security Act that will bring faster cuts in US carbon emissions.

The rate of change is important, on the highway, or with climate change policy. Strong legislation now that puts the brakes on our emissions will help us avoid a catastrophic impact with that wall of abrupt climate change. Contact your Senators today.


Peter Sawtell
Executive Director
Eco-Justice Ministries

Eco-Justice Ministries   *   400 S Williams St, Denver, CO   80209   *   Home Page:
Eco-Justice Ministries ended all programming on July 31, 2020. This site is an archive of writings and resources.
To contact a representative of the agency by e-mail, please use the contact form