The evidence that humans are causing climate change, with drastic consequences for life on the planet, is overhwelming, but the question of what to do about it remains controversial. Economics, sociology, and politics are all important factors in planning for the future.
A global conversation that began with concern over warming has now turned to the broader term climate change, preferred by scientists to describe the complex shifts now affecting our planet’s weather and climate systems. Climate change encompasses not only rising average temperatures but also extreme weather events, shifting wildlife populations and habitats, rising seas, and a range of other impacts. All of these changes are emerging as humans continue to add heat-trapping greenhouse gases to the atmosphere.
Countries around the world acknowledged the imperative to act on climate change with the Paris Agreement in 2015, making pledges to reduce greenhouse gas pollution. The Intergovernmental Panel on Climate Change (IPCC), which synthesizes the scientific consensus on the issue, has set a goal of keeping warming under 2 degrees Celsius (3.6 Fahrenheit) and pursuing an even lower warming cap of 1.5 degrees Celsius (2.7 Fahrenheit).
Both of those targets are in jeopardy. Major countries are already falling behind on their pledges, according to a UN report issued at the end of 2018, and emissions levels in 2030 need to be approximately 25 to 55 percent lower than they were in 2017. Previous research suggests that even if countries do meet their pledges to reduce emissions, those commitments won't be enough to stave off severe warming.
What can be done?
Addressing climate change will require many solutions—there's no magic bullet. Yet nearly all of these solutions exist today, and many of them hinge on humans changing the way we behave, shifting the way we make and consume energy. The required changes span technologies, behaviors, and policies that encourage less waste and smarter use of our resources. For example, improvements to energy efficiency and vehicle fuel economy, increases in wind and solar power, biofuels from organic waste, setting a price on carbon, and protecting forests are all potent ways to reduce the amount of carbon dioxide and other gases trapping heat on the planet.
Scientists are also working on ways to sustainably produce hydrogen, most of which is currently derived from natural gas, to feed zero-emission fuel cells for transportation and electricity. Other efforts are aimed at building better batteries to store renewable energy; engineering a smarter electric grid; and capturing carbon dioxide from power plants and other sources with the goal of storing it underground or turning it into valuable products such as gasoline. Some people argue that nuclear power—despite concerns over safety, water use, and toxic waste—should also be part of the solution, because nuclear plants don't contribute any direct air pollution while operating.
While halting new greenhouse gas emissions is critical, scientists have also emphasized that we need to extract existing carbon dioxide from the atmosphere. More fanciful ideas for cooling the planet—so-called “geoengineering” schemes such as spraying sunlight-reflecting aerosols into the air or blocking the sun with a giant space mirror—have largely been dismissed because they may pose more environmental risks than proven benefits.
But planting trees, restoring seagrasses, and boosting the use of agricultural cover crops could help clean up significant amounts of carbon dioxide. Restoring forests already chopped down in Brazil, for example, could draw about 1.5 billion metric tons of CO2 out of the air, and a recent study published by the National Academies of Science estimates the world’s forests and farms could store 2.5 gigatons. Those are relatively modest numbers given historic carbon emissions of 2.2 trillion metric tons, but every contribution is needed to curtail the world’s current trajectory.
Adapt or else
Communities around the world are already recognizing that adaptation must also be part of the response to climate change. From flood-prone coastal towns to regions facing increased droughts and fires, a new wave of initiatives focuses on boosting resilience. Those include managing or preventing land erosion, building microgrids and other energy systems built to withstand disruptions, and designing buildings with rising sea levels in mind.
Recent books such as Drawdown and Designing Climate Solutions have proposed bold and comprehensive yet simple plans for reversing our current course. The ideas vary, but the message is consistent: We already have many of the tools needed to address climate change. Some of the concepts are broad ones that governments and businesses must implement, but many other ideas involve changes that anyone can make—eating less meat, for example, or rethinking your modes of transport.
"We have the technology today to rapidly move to a clean energy system," write the authors of Designing Climate Solutions. "And the price of that future, without counting environmental benefits, is about the same as that of a carbon-intensive future."