by Rep. Jerry McNerney

Even if human beings were to cease all greenhouse gas emissions tomorrow, significant atmospheric change has already begun and will continue for generations. While there is no substitute for drastically reducing carbon pollution, we must explore all possible options to fight against the impending effects of climate change. This is critical for the future of our nation and planet.

That is why I pushed for a hearing last month in the U.S. House of Representatives Committee on Science, Space & Technology, to engage geoengineering experts in a discussion about the potential use of these mechanisms to combat climate change. A federal commitment to research is now in order, and, earlier this month, I introduced legislation calling for a modest federally funded program to lay out a research plan to determine the potential opportunities and risks of geoengineering.

As climate change affects everything from our infrastructure to agriculture and even national security, we must ensure our systems and structures can withstand forthcoming natural disasters. This means investing in scientific research, including geoengineering. The first and most critical step in this is process is committing to basic research to better understand the two mechanisms used in geoengineering: the removal of carbon from the atmosphere and the reduction of sunlight to counteract temperature rise.

Carbon removal can be accomplished through a number of actions, such as planting an abundance of trees or seeding the ocean to grow more carbon-absorbing plants like seaweeds. Sunlight reduction, also known as albedo modification, employs two techniques aimed at reflecting the sun. Cloud brightening, which involves adding more vapor into the atmosphere to whiten clouds and increase reflectivity, and the introduction of reflective sulfur or other particles into the atmosphere to reduce the amount of sunlight that gets through to the Earth. However, while sunlight reduction offers a possible approach to rising temperatures, there is also the potential for great risk that must be thoroughly examined before any possible deployment of this technology.

Some research in this field has already taken place, but lingering questions remain. For example, scientists have observed that sulfur emitted into the atmosphere from volcanic eruptions can reflect enough sunlight to temporarily reduce global temperatures, but it is unknown whether humans can responsibly introduce sulfur or other reflective particles. Deploying uninvestigated and unregulated programs could cause significant changes in weather patterns, potentially leading to droughts in historically wet regions or flooding in desert areas.

The atmospheric buildup of greenhouse gases — especially carbon dioxide — has a delayed effect on our climate. As heat builds up, it takes years or decades to manifest as clearly identifiable changes in the environment. Thus, today, we are experiencing the results from greenhouse gases dumped into the atmosphere years ago.

Recently in California, we have suffered the most severe droughts and related wildfires the state has ever seen; and in the United States and around the globe, coastal regions are facing frequent flooding that exceeds anything in historical record. But these are not the only, or even the most dangerous, results of advancing climate change.

Severe droughts in other parts of the world have been credited as the root cause of violent conflicts and civil wars, and vanishing glaciers are predicted to bring famine to certain regions. Additionally, we have seen in recent years that viruses like Zika and the migration of biological systems, as well as their rapid decline, have been linked to rising temperatures worldwide. With these serious effects rapidly unfolding, we must begin to plan and take steps toward preventing the worst impacts of climate change.

As we continue to examine all of the tools we have to combat this issue, we must redouble our commitment to emissions reduction practices that curb carbon buildup. This can be accomplished through a combination of legislative and regulatory means that promote the reduction of emissions and shift us toward clean energy. We should also systematically reduce emissions through the introduction of a carbon tax or other market-based programs, which would aid in combatting this issue while simultaneously growing the American economy.

Climate change has been labeled as one of the greatest challenges of our time, and geoengineering is just one potential tool we may have to combat its imminent effects. Americans have always chosen the path that leads us forward by investing in innovation and research. We must continue that tradition as we look to our nation’s future and our role in combatting climate change and other threats to global civilization.

Jerry McNerney is one of two scientists in Congress, with a background in engineering and a focus on renewable energy. He represents portions of San Joaquin, Contra Costa and Sacramento counties in the U.S. House of Representatives. To comment, submit your letter to the editor at SFChronicle.com/letters.

Brightening a cloud

Clouds have enormous impact on global temperature. That’s why geoengineers are considering a strategy of “brightening” clouds to offset global warming. Dispersing aerosolized saltwater or sulfate particles in the atmosphere could increase clouds’ capacity to block and reflect back the sun’s rays into space, and thus cool the planet. More research is needed to better understand how the process works