Some people believe that the urgency for action on climate change is overblown and that the rush for a quick fix due to “climate hysteria” will have a negative economic impact. Importantly, there is an enormous economic opportunity around green energy. We should not cling to a doomed energy source.
The issue is not local weather; it is the global climate. The greenhouse gas emissions that cause climate change today started with the industrial revolution. These emissions are being compounded every year with the continued use of fossil fuel. When greenhouse gases like carbon dioxide or methane are put into the atmosphere, they remain there for centuries. We do not question the sincerity of climate deniers. We question their scientific expertise.
Astronomers recognize the urgency of this problem. Everyone in the world is affected, or will be.
Climate change is resulting in an increasing number of forest fires. In 2020, there were 58,950 wildfires that burned 10.1 million acres. This compares to 18,229 wildfires that burned 1.3 million acres in 198. The increasing number and scale of fires result in a disasterous loss of life and homes, and release the carbon stored by those trees into the atmosphere, accelerating climate change.
Even when wildfires are several miles away from our telescopes, we cannot work because the domes must remain closed to protect the mirrors and optics of telescopes from high particle counts. In the past few years, forest fires have come perilously close to observatories, forcing evacuations and threatening buildings at Mt Graham (Arizona, 2004), Mt Wilson (California, 2018), Lick Observatory (California, 2020) and Lowell Observatory (Arizona, 2021).
Scientists agree about the fundamental climate data: both atmospheric carbon dioxide (CO2) and mean global temperatures have been rising since the industrial revolution. Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies said, “The thing to remember is that it’s clear that the best time to have reduced emissions was 25 years ago. But the second best time to reduce emissions is right now.
It is true that both CO2 levels and temperatures on Earth have cycled together over the measured history (about the last 800,000 years) of the Earth because of natural events. However, CO2 levels today have surpassed those historical records. The climate change that now threatens us is the result of CO2 emission from fossil fuel use.
It is true that “greenhouse gases” such as methane, carbon dioxide, nitrogen oxide and water have always existed in the atmosphere of the Earth. These molecules trap radiation from the Sun in the same way that rolled-up windows on your car will trap solar energy and warm up the interior. A small amount of greenhouse gases is a good thing; without them, our planet would be a giant “snowball” with frozen oceans.
All of the data agree! Multiple studies show the same thing: the global temperature anomaly began rising during the industrial revolution and is tightly correlated with increasing levels of carbon dioxide from the use of fossil fuel. At least 97% of the scientific community agrees with the interpretation of these data. Rolling forward, we can expect the global temperature anomaly to pass 4 degrees unless we act now. Animation credit: NASA
Climate is systemic and planet-wide, not local. Climate is not the same as weather. Climate is systemic and planet-wide, not local. It cannot be sensed by the individual. It must be carefully measured and averaged over the planet. It is the relative change in the temperature (the global temperature anomaly) over a historical reference value, that is key.
An increase of a few degrees may not sound so bad. An increase of a few degrees in global temperature may not sound so bad; people commonly experience temperature changes of many degrees throughout the year. The effects of global climate change are not immediately apparent when you walk out your door in the morning. However, an increase of even one degree in the global temperature anomaly has profound implications, increasing drought, fire, floods from rising sea levels, hurricanes, and changing the ocean currents.
What we do today is not immediately apparent. There is a lag in the atmospheric response, making it hard to see the cause-and-effect. But the Earth’s atmosphere remembers the collective emission of greenhouse gases. Even if we stop all CO2 emissions, there will be a multi-year delay before CO2 leaves the atmosphere.
Climate change models are complex & unfamiliar. Predictions of an increasing global temperature anomaly are based on mathematical computer simulations, a tool that may not be familiar to non-scientists. However, modeling and simulations are used regularly by scientists. If you use a cell phone, it works because of computer simulations used to launch communication satellites. While climate change models are complex, they have been validated by the accuracy of past predictions.
Change comes at some cost. The required changes in human behavior come at some cost. People naturally want to be sure that these changes are warranted. Scientists are so convinced that they are adopting real changes in their lives to reduce CO2 emissions.
Social psychological distress is real. Psychologists note that if an individual is part of a social group that does not accept climate change, the threat of rejecting the beliefs of their community may be more distressing than the threat of climate change.
There are many important issues facing people today, including health care, immigration, the global economy, racism, domestic and foreign policy, environmental issues. In fact, these issues are interconnected and there is value in working for progress on all fronts. However, the scale of climate change is staggering and it amplifies all of the other issues noted above. Climate change presents a systematic, fundamental threat to humanity. Lifestyles of the wealthy are correlated with more carbon dioxide emission, but climate change will have a disproportionate effect on people who cannot afford to relocate their homes.
We can see the impact of climate change on immigration. Some of the people appearing at the southern borders of the U.S. are leaving Guatemala at least in part because persistent droughts are decimating the crop production of local farms. They are facing starvation and a loss of their livelihood. Climate change simulations predicted reduced crop production resulting in displacement of populations.
A sixth mass extinction is now underway on Earth. It has been estimated that dozens to hundreds of species of insects and animals vanish from our planet every day. The exact estimate is difficult to quantify, simply because we are just beginning to learn about the extensive diversity on Earth. Humans are connected to other species by co-evolution. Species extinction means the permanent loss of potential scientific and medical discoveries and holes in our understanding of the rich fabric of life on our planet.
It can be hard to reconcile the impact of hurricanes and a burning amazon rain forest with what you see when you walk out the door on a beautiful sunny day.
Climate models, or simulations, predict the future response of our climate to increasing greenhouse gases. These models have been refined over the past decades and include all of the physics and chemistry of the atmosphere that we know. There are still some uncertainties (such as the role of aerosols), but these models provide evidence that climate change is an existential threat.
The Center for Global Change Science at the Massachusetts Institute of Technology (MIT) was established in 1990 to develop realistic simulations that include the physics of climate change and the expected economic impact. Now, scientists and engineers at MIT, Caltech, and the Jet Propulsion Labs are teaming up to build a new climate model that will provide even more precise and actionable predictions.