Days before world leaders began meeting in Madrid to discuss climate change and global efforts to slow it, the United Nations released a report warning that global greenhouse gas emissions continue to increase.
“Countries collectively failed to stop the growth in global (greenhouse gas) emissions, meaning that deeper and faster cuts are now required,” says the United Nations Environment Program’s Emissions Gap Report, which lists the world’s top two polluters as China and the U.S. Those two countries increased emissions last year.
Certain gases, including carbon dioxide, methane, nitrous oxide and hydrofluorocarbons, act like a blanket in the atmosphere and prevent heat from escaping. Carbon dioxide accounts for the majority of climate change, and other gases are often recorded in “equivalent carbon dioxide emissions.”
Globally, the averaged concentrations of carbon dioxide reached 407.8 parts per million last year, up from 405.5 parts per million in 2017, according to the World Meteorological Organizations’ Greenhouse Gas Bulletin.
The concentrations of emissions represent what remains in the atmosphere after a system of interactions between the atmosphere, biosphere, lithosphere, cryosphere and the oceans. About 25 percent of total emissions are absorbed by the oceans and another 25 percent by the biosphere, according to the World Meteorological Organization.
Burning oil, gas and coal is the main source of greenhouse gas emissions, along with agriculture, deforestation and industry. Nearby, the Tennessee Valley Authority’s Paradise Fossil Plant – which is scheduled to retire by December 2020 – released 6,557,165 metric tons of equivalent CO2 in 2018, according to the Environmental Protection Agency’s Greenhouse Gas Reporting Program.
Regionally, in 2018, five “large facilities” reported the following equivalent CO2 emissions in metric tons: Southern Sanitation Landfill, 7,101; Logan Aluminum Inc., 199,406; Dart Container Corp. of Kentucky, 26,146; Real Alloy Recycling, 46,752; and the Glasgow Regional Landfill, 146,621, according to EPA.
But ultimately, it doesn’t matter where emissions originate.
“It’s not a locally confined system, it’s a global system,” said Stuart Foster, state climatologist, WKU professor and Kentucky Mesonet director. “The atmosphere becomes well-mixed.”
These emission levels heat the global atmosphere and the oceans, which has cascading effects like sea-level rise, worsened droughts and wildfires, biodiversity loss and more extreme weather. This atmospheric and oceanic heating is also long-lasting, according to Foster.
“It’s very difficult to put the breaks on the climate system,” Foster said. “It has a tremendous amount of inertia.”
“And the fact that we’re continuing to increase emissions makes the challenge moving forward that much more difficult.”
Scientists warn that nations must limit the global temperature increase above pre-industrial levels to 1.5 degrees Celsius to avoid the worst impacts of climate change. But there are already climate change impacts, and there will be more impacts at 1.5 degrees Celsius. Additional warming would further increase severe and expensive impacts, according to the UN report.
To limit warming, economies must cut emissions of carbon dioxide and other heat-trapping gases. That will require transitioning to 100 percent clean energy, using clean vehicle technologies, planting forests, significantly altering agricultural practices and using “negative emissions” technologies, according to the Union of Concerned Scientists, a science advocacy nonprofit.
That’s why countries across the world – excluding the U.S., which formally began to withdraw from the Paris Agreement last month – are working together to collectively reduce emissions. Under the current commitments, emissions will be about double what they should be in 2030, according to the UN report, which says global greenhouse gas emissions must fall 7.6 percent each year between 2020 and 2030.
Cities can also make impacts in the absence of or in addition to federal or global action.
In Bowling Green, both individuals and the community could work to become more energy efficient, reduce their carbon footprints and plant trees to provide carbon sinks, according to Foster.
“Ultimately, it’s a difficult thing,” Foster said. “It forces us to change our habits, which is not easy.”