Last week, the Intergovernmental Panel on Climate Change released its executive summary describing the consequences of continued greenhouse gas emissions, such as carbon dioxide (CO2), on our planet. It is important to note that warming the Earth is just one of the many consequences of increased man-made CO2 in the atmosphere.

Less appreciated, but equally important, is the fact that rising CO2 also influences the growth of plants and animals on the land and in the oceans in ways that will alter the productivity of the Earth on which our lives depend.

The science on these changes is clear: If the increase in CO2 is not abated, our ocean fisheries will be at risk, the quality of agricultural food products will be reduced, and our Western landscapes, which support tourism and the continued economic development of our state, will be fundamentally changed.

The expected changes are sufficiently dramatic that both personal and government action is warranted.

Adding CO2 to the atmosphere is making the oceans more acidic. This change in ocean chemistry is placing our world's fisheries at risk. The increased acidity reduces the growth of plankton, the microscopic organisms that are the foundation of ocean food webs.

Less plankton means less energy for organisms higher in the food chain. The net result? Fewer fish — which means less food for the people who depend on oceans for their livelihood.

Adding CO2 to the atmosphere also has a negative effect on the agricultural plants that feed the world. Rice, a food crop that sustains about one-half of the people on Earth, will become less nutritious. Rice has 15 percent less protein when grown at the CO2 concentrations that are predicted to occur by midcentury. Similar changes occur in other crops, including wheat.

For a large fraction of the Earth's population, this reduction in the protein content will increase malnutrition and exacerbate the effects of famine. The decrease in the nutritional value of food crops will occur regardless of how CO2 affects global temperature.

Rising atmospheric CO2 also threatens the beloved landscapes of our American West. What will the landscapes we call home look like in the future? Rising CO2 will change them also, by promoting the growth of nonnative plants and increasing wildfires in areas that are not fire-adapted. Such fires are already removing iconic desert plants from the landscape.

Saguaro and Joshua Tree national parks will end up without the signature species these parks were designed to protect. These changes place our tourism industry at risk. Arizona will lose its saguaro, the Mojave Desert will lose its Joshua tree, and the great basin desert's vast stretches of sagebrush will be no more.

We should not wait for government to act. This is a case where individual action can make a difference. There are many solutions that result from small changes in personal energy consumption, from turning off lights when you leave a room to washing your hands in cold water, to supporting alternative energy sources, especially those related to transportation.

Do not be distracted by special-interest groups arguing over the degree of human-caused warming. Keep in mind these direct effects of rising atmospheric CO2 on our natural world, and use them to motivate you to start to make a difference.