One of the few beneficial aspects of the global pandemic was a sharp reduction in pollution at all levels, including greenhouse gas emissions.

China was the first country to lock down in January 2020, prohibiting people from even leaving their homes for several weeks. The result? Air pollution declined at a rate never before seen. As the virus spread and one country after another curtailed activities, worldwide pollution levels plummeted. Much of that decline was driven by a sharp reduction in all forms of transportation, which is the main contributor to greenhouse gases in the U.S. and here in Minnesota.

What we experienced was a real-time experiment in the impact of human activity on our planet and what would happen if we could radically reduce our reliance on fossil fuels.

But as economic activity has resumed, so has pollution. After dramatic reductions in 2020, U.S. emission rates soared by more than 6% last year and are expected to continue rising as the economy reaches higher levels of normalcy.

President Joe Biden wants to cut greenhouse gas emissions 50% below 2005 levels by 2030, a goal that experts said the world should follow to prevent the planet from further warming and the extreme weather events expected to accompany it.

But durable progress has been painstakingly slow. So far, with everything the country has done to spur development of alternative energy sources, U.S. emission levels are only 17.4% below those 2005 levels.

The Build Back Better Act that would aim more than $500 billion at renewable power, electric vehicles, electric stations, solar and other programs could, according to Princeton researchers, get the U.S. close to its goal. But the bill remains stuck in the Senate, where Joe Manchin of West Virginia, a coal state, has proved difficult to win over.

Minnesota has faced similar issues in its push to combat climate change. In 2007, then-Gov. Tim Pawlenty signed the Next Generation Energy Act (NGEA), which aimed at reducing carbon emissions and supporting clean, renewable energy in the state. It included statutory goals to reduce emissions 15% by 2015 and 30% by 2025. We missed the first goal and are not on track to meet the second.

In 2019, Gov. Tim Walz signed the Climate Change Executive Order (19-37), aimed at measures that could protect the state from the worst impacts of climate change. The state now has a Climate Change Subcabinet and a Governor's Advisory Council that uses a citizen board to advise the subcabinet.

Time is growing short. University of Minnesota Climate Science Prof. Heidi Roop, in 2021 testimony before a state House committee, said that 2020 tied for the warmest year on record nationally, with 22 disasters that cost $1 billion or more for a combined total of $95 billion. Climate change is causing extreme heat and increasingly severe droughts, storms and floods. Those changes, she said, create stress on roads and buildings, bridge expansion, joints, water infrastructure and railroad tracks.

We are no longer in a position to stave off climate change. That time has long passed, time squandered in endless debate over whether climate change was caused by human activity. But we do still have time to work together to mitigate the worst effects. We know some of the actions that must be taken. We know we must lessen dependence on fossil fuels.

Sixteen cities across Minnesota recently declared climate change emergencies to send their strongest possible signal to the state Legislature that it must take concrete action and soon. From Moorhead to Red Wing, from Grand Marais and Duluth to Rochester, city leaders are banding together. That is the kind of leadership from the ground up that can and must drive change.

A year ago, Frank Kohlasch, climate director at the Minnesota Pollution Control Agency (MPCA), said that "while it will be challenging to move ahead in light of where we've been with COVID and economic slowdown, this is an opportunity to … take important and significant action on climate change."

The COVID crisis proved far deeper and more durable than anyone could have imagined. But that immediate emergency does not dispel the gathering threat of climate change.