RFF President Richard G. Newell makes the case for welcoming a range of potential solutions to tackle the global climate challenge while meeting the world’s energy and economic needs.
Over roughly the last decade, renewable energy sources—wind and solar in particular—have become dramatically less costly and are starting to play a major role in parts of our energy system. But at the global level, these technologies have mostly added to—not displaced—the incumbent energy sources of the past. The world uses more coal than ever before, more oil, and more natural gas. Today, fossil fuels still account for over 80 percent of global primary energy demand.
This energy, and the emissions that come with it, are used across the economy—in industry, buildings, and transportation. In addition, a sizable portion of global greenhouse gas emissions comes from non-energy activities, such as agriculture, forestry, and other land-use practices, plus process emissions from cement, chemicals, steel, and other industries. So, as we think about the climate challenge, let’s keep in mind that while energy accounts for about 70 percent of global emissions, it is not the only source. We therefore require a wide range of solutions that cut across disparate sectors of the economy.
As global population and income continue to rise, the world has made modest progress on bending the emissions curve. The US and global energy systems have become more efficient, with less energy input per unit of gross domestic product. The carbon intensity of the energy system has also declined—slightly at a global level and more so in the United States and Europe. Nonetheless, global carbon dioxide emissions continue to rise. After an additional 50 gigatons of carbon dioxide equivalent entered the atmosphere just last year, the atmospheric concentration of carbon dioxide now hovers at around 410 parts per million. For all greenhouse gases, the concentration is at 450 parts per million of carbon dioxide equivalent—higher than it has been for at least 800,000 years. As long as net emissions are above zero, global concentrations will continue to rise.
The consequences of this increasing concentration of greenhouse gases are stark. The average global temperature has already risen by 1°C, and some regions have had to confront temperature increases more than twice that amount. As more gases accumulate in our atmosphere, global temperatures will only increase.
Changing our global energy system comes with many challenges and costs. But the costs of inaction are clearly much higher.
At the rate we have been adding emissions, we’re on a path to more than triple the amount of greenhouse gases in the atmosphere by the end of the century, leading to average temperature increases of more than 4°C (or 7°F). This is the global average; in some regions, the temperature increase would be much higher. If we include commitments made by nations under the Paris Agreement, some estimates suggest that we could limit average warming to around 3°C by 2100.
The resulting negative impacts are well known, including more heat waves, extreme weather, wildfires, rising sea levels, increased acidification of oceans, and a heightened risk of abrupt and irreversible damage to our planet. To reduce the likelihood of the worst outcomes of climate change, we need to accelerate the shifts in our energy systems and look toward new solutions to manage risks.
The Ultimate Endpoint
Since the beginning of international cooperation on the climate issue, global goals for managing greenhouse gas emissions have been ambitious. Back in 1992, virtually all nations agreed in the UN Framework Convention on Climate Change to the objective of “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”
“Stabilization” here implies that humans must head in a direction where our net contribution of greenhouse gases to the atmosphere is zero, meaning we cannot add more than we take out. Defining “dangerous interference” is more co