How to save the planet

The news is grim. New measurements show that the climate-changing gas carbon dioxide is at the highest atmospheric concentrations — 400 parts per million — in at least 3 million years. Evolved human beings have never seen it like this. And yet a recent Gallup poll shows that only a minority of Americans — 50 percent of Democrats and 18 percent of Republicans — believe that global warming will "pose a serious threat to them or to their way of life during their lifetime."

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With such a disconnect and so little political will, action seems impossible. But there is a way. There are many things we can do ourselves if we shift our focus from climate change to the well-established biological concept of carrying capacity.

Carrying capacity is the maximum population size that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment.

We'll get to the math later, but it works out that if only a minority of the population reduced their footprint by 25 percent right now, eventually increasing to half the population by 2050, it might be possible to avoid crossing a point of no return, a tipping point for the planet. That is not an unreasonable possibility. To be sure, individuals will still need to push institutions to change, but the answer, fortunately can start within ourselves.

Let's begin with an analogy. Think of a rowboat that can hold a limited number of people. Add one too many, and the boat will sink. Everyone drowns. Likewise, the planet can support a limited number of people. Add too many and its capacity to support life will collapse.

In a rowboat, it is not the number of people but their combined weight that matters. For the planet, this is the "effective population;" it is the number of people multiplied by their average impact that is the total burden of the human footprint on the planet. As you might guess, an American has a much bigger footprint than someone from the developing world, where population growth is fastest.

Additionally, a rowboat, when exposed to stormy weather, rocks and dips in ways it did not when the water was still. Nature is the same. When a growing population cuts down trees to clear land to grow food, the result is soil erosion decreasing the amount of food to feed the increasing number of people who are cutting down the trees.

When collapse occurs in nature, there is a "tipping point" in which the accelerating demands produce a rapid decline in capacity. The process is similar to the overcrowded rowboat that, with the addition of a small amount of extra weight, starts to take on water and quickly sinks. Once the tipping point is crossed, neither the boat nor nature can support life. For thousands of years this has not been an issue for the planet. It is today.

Fortunately, we can do something about it. And in surprising ways, the math works in our favor, if enough of us change our ways. If, between now and 2015, just 3 percent of the effective population would reduce their total footprint by 25 percent, and by 2020 the percent doing so doubled to 6 percent, and by 2030 double again to 12.5 percent, and by 2040 to 25 percent, and by 2050 to 50 percent, then the total footprint of the effective population would be reduced, the planet could start to recover, and the danger of crossing the tipping point would be averted. The collective effective footprint of the human population on the Earth would start to decrease at around 8 billion, even though the actual population is projected to reach 9 billion by 2050.

The impact of total distances traveled and the efficiency of transportation, the amount and sources of energy used, and what we eat and how it is produced can each be divided into subcategories, which can be further broken down to the number of gallons of gasoline, diesel and aviation fuel refined; the tons of fertilizer and pesticides used; the number of wind farms created; and the BTUs of coal and oil that must be remain in the ground. These can all be measured. They are all subject to public political control, and the policies required to regulate these events are known.

This challenge is of particular relevance to those of us living in the United States, because we are putting in jeopardy our way of life, far more so than China, which is our major competitor.

While China contributes more to carbon emissions, its population is four times larger. Per person, it is we who are the biggest offender in the world of overuse of natural resources. We have more to lose than any other nation if, collectively, the human race exceeds the carrying capacity of the planet. And it is within our power, personally and politically, to reduce our footprint and the effective size of our population — in other words, the per person load we put on the planet.

A small percentage of people making regular small contributions, and encouraging progressively more people to join with them, can have a large cumulative effect. These individual efforts are all necessary, but they alone are insufficient. Rather, they must be our daily reminder that public policy issues, such as effective mass transit to replace commuting by car, the infrastructure of alternative energy sources and national policies independent of the short-term self-interest of big agriculture, big oil and multinational corporations are also essential. Averting a crisis in our lifetimes doesn't make the Earth habitable forever.

The same new dire report on carbon dioxide offers one hopeful and helpful note. It points out that atmospheric levels will briefly dip this summer before heading back up to ever more dangerous levels. Why? Trees will leaf out and absorb carbon dioxide during photosynthesis in the Northern Hemisphere, which contains the majority of the Earth's land mass.

This temporary natural relief does not have to be seasonal. In the short term, we have direct personal control over hundreds of specific everyday actions, such as using fewer plastic water bottles, driving one less mile, eating less meat, planting a garden and eating seasonal local produce, among a long list. Every bit counts.

In the longer term, if a growing number of us change our personal ways, we will begin to build the necessary social and political awareness to shift our focus away from the abstract event of climate change to government and corporate accountability for specific and measurable policies and practices of not using more resources and producing more waste than the planet can replace or absorb in a year.

Add them up, and we can save the planet.

Edward Renner is a professor in the Honors College of the University of South Florida. He may be contacted at The environmental data is from the Global Footprint Network data base: He wrote this exclusively for the Tampa Bay Times.

World population growth

For 6,000 years of recorded history the number of people on Earth increased gradually. With industrialization, modern medicine and mechanized agriculture, the number of people has risen so rapidly that we are in danger of sinking the good ship Earth with all those aboard within the lifetime of the majority of people alive today. In relative terms, a house that held four people in 1940 would be home to 13 today. The solutions are ones we have to find now; there is not time for them to be left for our children to solve.

The U.S.-China overshoot

This chart compares the "carrying capacity" (the biocapacity) of China and the United States with the "carbon footprint" of an average resident of each country. The United States has a higher biocapacity per capita, but it also has a far bigger average footprint. Both countries are outpacing their landmasses' capacities, but the gap is much wider for the United States. (A hectare is 2.47 acres.)

The United States has been using more resources and producing more waste longer and to a greater extent than any other nation. Other countries have been our environmental creditors. Some are becoming resentful and unwilling to continue to carry our ecological deficit. Because we share a common planet, any effective solution must be a cooperative international response. We cannot other countries to indefinitely support the size of our overshoot at the relative expense of its own population. We are in a position to lead the world in a positive direction.

Avoiding the Tipping Point

This chart shows the trend lines for the "carrying capacity" of the Earth and the globe's rising population. When the two lines cross, the planet can't support the people. A tipping point occurs when the cascading bad effects multiply and reinforce each other's damaging effects, bringing trouble faster and faster. But reducing our footprint can "bend" the population curve down by reducing the load each of us places on the planet, and letting the Earth heal itself can "bend" the carrying capacity curve upward. Changing those two trends would keep the lines from crossing.

If over the next two years, 3 percent of the population reduces its footprint by 25 percent, and the percentage of the population doing so increased to 50 percent by 2050 the effective size of the human footprint would peak at 8 billion and then begin to decline. As a result of reversing our destruction of the biocapacity of the Earth, nature can begin the recovery process, such as allowing the rain forest to regenerate new areas and reclaim grass lands to sequester nitrous oxide and support grazing. We know that when nature is allowed to heal our biocapacity will slowly start to recover. For an interactive graphic to see the effects of different final participation rates and footprint reductions go to

How to save the planet 05/18/13 [Last modified: Friday, May 17, 2013 4:46pm]

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