Timing is everything. In 1980, I was living in Washington state. In March, a large earthquake in the vicinity of Mount St. Helens, an active volcano, rocked the landscape and soon thereafter steam began to vent from the mountain. By late April, a large bulge appeared on the north side of the mountain. On May 18, a massive eruption occurred, taking off the top 1300 feet of the mountain. The devastation was awesome. Although 57 people died, geologists were able to warn nearby residents of the risk and many evacuated the area. The risk was imminent so people reacted.
We see the same behavior with hurricanes. When a hurricane is likely to hit the coast, residents are warned and many evacuate with just a few days warning.
Now we are experiencing the COVID-19 pandemic. The pace of the pandemic is more moderate and will certainly occur over many months. In some states like Maine, the number of cases is modest with around 20 new cases reported each day. Stay-at-home mandates, social distancing and the closure of non-essential businesses are taking a toll on all of us. But we know these responses are necessary because the COVID-19 virus can spread so quickly and models tell us we can flatten the curve of cases by reducing contact with each other. However, we are starting to see flouting and protests of stay-at-home mandates across the country. I think one explanation is that COVID-19 is spreading slowly and the urgency of our response is seen by some as overreacting.
With Earth Day recently passed, I want to continue this theme of timing by considering what I think is the greatest threat to our earth: climate change. From the origin of humans about 150,000 years ago until 200 years ago, carbon dioxide levels in the atmosphere were steady around 275 parts per million (ppm). But with the rise of the Industrial Revolution, CO2 levels have been steadily rising, now over 400 ppm. The greenhouse effect produced by the ever increasing CO2 in the atmosphere is a major driver of global warming. These changes are incremental, occurring over many years so many people, including many politicians, do not see an imminent threat and hence feel no urgency to try to curtail CO2 emissions.
Two recent scientific articles sound the alarm for our bird populations with respect to climate change. In September of 2019, an article appeared in the journal Science by Ken Rosenberg and colleagues. Using Breeding Bird Survey data and other long-term data sets, they found that North American bird populations have lost three billion birds compared to populations 50 years ago. That is a reduction of 29%. Of the 519 species analyzed, 57.4% are in a state of decline. Climate change is an important factor in driving these declines.
In April, an article by Christopher Trisos and colleagues appeared in the journal Nature. The researchers used temperature and rainfall data since 1850 to predict the environmental limits of 30,000 species of plants and animals from both the terrestrial and marine realms.
If global warming continues at its current pace, their model predicts not just isolated extinctions but the collapse of entire communities and ecosystems. These collapses may occur in the oceans by 2030 and in terrestrial habitats by 2050. These drastic extinctions would be devastating. The authors argue that if we can keep the earth from warming by 3.6 degrees Fahrenheit, these abrupt losses of biodiversity can be averted. We have to get global warming under control.
Some people who oppose efforts to halt global warming argue that there have been times in earth’s history when the climate was much warmer than it is now. That claim is absolutely true. However, the rate at which the earth warms and cool was much more gradual than the rate in our current time. Ancient organisms had time to adapt to a warming or a cooling earth. The rate at which human activities are warming our globe is unprecedented. Timing is everything.