A decade of decision: Understanding climate change

October 27, 2021
Peter Goodwin


In early November, the 2021 United Nations Climate Change Conference meets in Scotland to assess progress in tackling the global priority of climate change. The latest report from the Intergovernmental Panel on Climate Change described global warming as real and the scientific evidence “unequivocal”. Every region of the world can expect to be impacted by extreme events unless greenhouse gases are reduced and the rise in global temperatures limited.

University of Maryland Center for Environmental Science President Peter Goodwin says there is still time to act, but we are operating in a very narrow window. He answers some basic questions about climate change and Maryland.

What is the COP 26 UN Climate Change Conference?

The world leaders are gathering to decide what actions should be considered because right now we are on track for 2.7 degrees C (4.9 degrees F) warming by the end of the century, which by almost all measures could be catastrophic. Science is saying if we can restrict the increase in temperature to 1.5 degrees C (2.7 degrees F) by the end of the century, there is a chance that society and the environment can adapt in time.

What difference could a couple of degrees make?

What we have to realize is that our atmosphere is very finely balanced—2 or 3 degrees does not sound much, but it can be a tipping point and change the atmospheric circulation that then also has a significant influence on the circulation in our oceans. These combined effects continue to change the weather and to accelerate these processes. As a result of the shifting weather patterns, some of the most sensitive areas on the planet are impacted. Antarctica and the Arctic Greenland are extremely sensitive to these subtle changes in temperature because it accelerates melting of ice sheets and diminishes ice cover on the sea. The loss of ice cover  affects the reflectivity of the sun’s energy hitting the earth, and a diminishing of light-reflective areas results in further warming processes.

The world's seven warmest years on record have all occurred since 2014, 2020 being the second warmest on record behind 2016.

What is causing global warming?

The latest report put out by the Intergovernmental Panel on Climate Change has said the scientific evidence of a warming climate is irrefutable. What this means is that since the Industrial Age the world has been putting greenhouse gases into the atmosphere at very high levels, and it’s those greenhouse gases that absorb the sun’s heat and energy, warming the atmosphere.

Global temperatures are expected to rise by 2.7 C by the end of the century.


Greenhouse gases come from many different sources. The big ones we talk about are carbon dioxide, nitrogen oxide, and methane Carbon dioxide comes out of the car you are driving around, and it comes out of energy production, like coal-fired power plants. That’s why we spend so much attention trying to move away from coal-fired power plants to natural gas and renewable energy sources.

We also see some greenhouse gases entering the atmosphere through natural processes, such as forest fires, changes in wetland characteristics, and the melting of the tundra at the poles. As the planet warms and we experience more frequent and intense extremes, these processes are also accelerating.  And the loss of tree cover due to deforestation or wildfires not only gives up carbon, it also limits nature's ability to recover by absorbing carbon dioxide through photosynthesis.

The planet is always changing…what is different this time?

It’s absolutely true that the globe has gone through cycles over the millennia, but what’s different in this instance is the rate at which the planet is warming and the rate of increase of carbon dioxide is unprecedented. That is why there is so much cause for concern. The greater frequency of extreme floods, droughts, and weather events is being attributed to global warming, along with changes happening so rapidly in our natural environment that many plants and animal species simply cannot adapt fast enough to these changes, contributing to a loss of biodiversity in many places around the world.

What does climate change look like in Maryland?

If you think back to the Boat Show in Annapolis in 2019, extraordinarily high tides associated with Tropical Storm Melissa, compounded by sea-level rise, put much of the boat show under water. The 2016 storm in Ellicott City dumped 5 inches of rain in 2 hours, but this was eclipsed in the 2018 storm when more than 10 inches of rain fell in less than 2 hours. To have such extreme storms in a period of 3 years is statistically very surprising.

Another critically important factor we are seeing is an increase in the number of hot days or exceedingly hot days, and the duration of these heatwaves.  This is compounded in cities like Baltimore that experience the “heat island effect,” where roads and structures absorb and re-emit heat, causing  urbanized areas to feel even warmer. It is not just a matter of feeling uncomfortable for a few days, but it’s a matter of life and death if you can’t get out of the heat, particularly for many of our underserved communities or those with health issues.

How is sea level rise impacting Maryland and the Chesapeake Bay?

The Chesapeake Bay is a very highly valued resource by virtually everybody living in this state, and this iconic shoreline is at risk all around the bay. It is very evident in some places like the Blackwater National Wildlife Refuge that has lost more than 5,000 acres since the 1930s. Here where you can see during regular high tides—something called nuisance or sunny day flooding—where roads are inundated. You can see the loss of not just wetlands, but you can actually see entire forests that are dying because of sea level rise and saltwater gradually encroaching on brackish and freshwater marshes. These are significant changes underway that are changing the landscape. We also know there are measures available to adapt, preserve and sustain many of these critically important habitats.

Sea level rise predictions for Maryland could be 2 feet by 2050, and 3-6’ by 2100.

It isn’t just the sea level rise that happens very slowly, but when the water is deeper, waves generated by major storms get closer to shorelines before breaking, which transfers more energy against the shoreline resulting in faster rates of erosion. We see residents having to replace their shore protection because they are losing land at a faster and faster rate, and we can anticipate that with sea level rise the erosion will become worse. We need to be thinking about innovative natural solutions to protect our homes and critical infrastructure around the bay.  Maryland has developed considerable expertise and experiences in these innovations.

This problem seems too big to solve. What can we do?

This has become the “decade of decision.” There is still time to act, but we are operating in a very narrow window. We need to take very dramatic actions to reduce carbon emissions and reduce the other greenhouse gases as quickly as possible. The science is saying that we really need to make very deep inroads in the reduction of these greenhouse gases before 2030, which is what the State of Maryland’s Greenhouse Gas Reduction plan is targeting.

What can I do personally?

There are many steps we can take individually. For those who can transition to an electric vehicle, that makes a very big difference. Just being mindful about the number of miles that we drive in a given week can make a very significant difference because vehicles account for about 40% of all of the production of greenhouse gases in the U.S.

Also giving much thought to reducing waste materials and maximizing recycling so we are not generating new plastics or consuming a lot of materials, all of which have a carbon footprint. Even simpler things that we don’t consider directly related to climate change, such as the reduction of water use. It’s costly to get water processed and pumped to your home.  So putting in water efficient shower heads and reducing the water used reduces the energy needed to heat the water— and reduces your utility bill.