The latest episode of Conversations in Science has now aired on KLRNRadio. It was a requested topic and given the current escalation of the news about climate change and global warming, I can understand why.
Is all this hoopla about global warming really fake science (alternative facts) or is it real and something we should be worried about? Simple answer: it's all real, but the issues and solutions are far from simple.
Climate Change: Is it Real or Fake Science?
(First aired on KLRNRadio, Monday, February 6, 2017)
The scientific concepts behind greenhouse gases and global warming are actually something that scientist have had a firm grasp of for over 100 years. In 1896, Swedish scientist Svante Arrhenius proposed the idea that fossil-fuel combustion could enhance natural global warming. He determined that the Earth's average surface temperature of 15°C (59°F) was because of the absorption of infrared radiation by water and carbon dioxide (CO2) forming a natural greenhouse effect. Arrhenius suggested that if the CO2 concentration in the atmosphere was to double, then we could expected an increase of 5°C (9°F) in our average surface temperature. Originally, Arrhenius had sought to determine if CO2 levels could be linked to the cause of the Ice Ages, a theory that wasn't verified until 1987.
Arrhenius's theories on global warming were quickly dismissed. People believed that human influences were insignificant compared to natural forces, such as solar activity and ocean circulation. They believed that because of the shear size of the oceans that the oceans themselves would be able to cancel out any man-made pollution. It was thought that water vapor had a much greater influence over the greenhouse effect than CO2. In a way, they were right, but they also couldn't have been more wrong.
A greenhouse gas is any substance that will absorb one form of radiation (UV, infrared, etc.) and emitted it as heat. Without greenhouse gases in our atmosphere, the planet would have an average surface temperature of -18°C (-0.4°F). I don't care if you look at that number in Celsius or Fahrenheit — THAT'S COLD! For life as we know it to exist on this planet, we need the greenhouse gases to help keep us warm, but different greenhouse gases do other things too.
Let's, for a moment, go back to this idea that the oceans were large enough to counter any man-made pollution. The water in the ocean does absorbs excess CO2 from the Earth's atmosphere, however, this absorption effects the acidity levels of the oceans; CO2 when dissolved in water forms carbonic acid. The oceans are naturally basic (the opposite of acidic), but they do fluctuate in their acidity levels. This is a natural process. However, the increased CO2 absorption has meant that the oceans have started to become more acidic, eating away at the coral reefs and plankton that all ocean life rely on. Shells of crabs and other shellfish are becoming thinner, making them more vulnerable.
Policy makers don't dispute that oceanic conditions are changing. Marine biologist can prove beyond a shadow of a doubt that current conditions have lead to a dramatic decline in the diversity of marine life. What is at dispute is how much of this change is a result of man-made pollution and this thing called Global Warming.
Let's turn our attention to something that is a known environmental effect that has been adversely affected by man-made pollution.
In the 1920s, it became commonplace to use CFCs (Chloro-Fluoro-Carbons) as a refrigerant. After WWII, CFCs became widely used as a propellant for insecticides, cosmetics and other things. The wide usage of CFCs was because these man-made chemicals were nontoxic and nonflammable. They were also highly stable and didn't breakdown — or so we thought.
In 1974, scientists were able to show a dramatic increase in inorganic chlorine in the stratosphere. (The stratosphere is the layer of the atmosphere that ranges from 8 km above ground at the poles through to 50 km above ground. Planes tend to fly through the stratosphere. The ozone layer is part of the stratosphere.) These random chlorine atoms where reacting with the ozone in our atmosphere and depleting the Earth's natural ability to shield itself from UV radiation. The source of these chlorine atoms... It turns out that CFCs breakdown into their elemental parts when exposed to UV radiation. These man-made chemicals destroy the Earth's ability to protect life on the surface.
The Sun emits a spectrum of UV radiation. The shortest wavelengths of UV radiation, known as UV-c, are deadly to life on Earth, but we're in luck — 100% of UV-c is filtered out by the oxygen and ozone in the Earth's atmosphere. On the other end of the spectrum, nearly all of the longest wavelengths of UV, known as UV-a, makes it through to the Earth's surface. UV-a is the least harmful, with premature aging of skin being linked to UV-a exposure. It's the mid-length UV rays, UV-b, that are the issue.
Majority of UV-b is block by ozone in the atmosphere, but NOT all. The levels of UV-b that does reach the ground can be linked to sunburn and skin cancer. With decreasing amounts of ozone in the atmosphere, more UV-b makes it through, which has led to an increase in skin cancer. Ironically, we need UV-b so our bodies can produce the Vitamin D needed for bone health.
The direct link of CFCs to the depletion of ozone led, in part, to the Montreal Protocol of 1987 in which 27 nations around the world agreed to reduce substances that depleted the ozone layer. As a result of that initiative, CFCs have now been banned. Unfortunately, even with the ban of CFCs, the damage has already been done. We now have these man-made chemicals floating around in the atmosphere and there are very few options on how to deal with them.
But what about our current activities?
By looking at the trapped air bubbles in polar and glacial ice, scientists are able to determine what the gases were floating around in the atmosphere at various points in history. From it, we've been able to obtain a historical record of CO2 concentrations.
During the ice ages, CO2 concentrations were at 200 parts per million (ppm). During warmer interglacial periods, CO2 concentrations measured 280 ppm. In 2013, levels were in excess of 400 ppm. This might not be double the levels found in 1896, but fact that we have climbed 100 ppm since 1950 is proof that current levels are man-made. In fact, scientists believe that if fossil-fuel burning was to continue, exhausting all reserves, then we can expect to see CO2 concentrations to climb to 1500 ppm.
Remember that Svante Arrhenius predicted that if the CO2 concentrations were to double, then we could expect a 5°C increase in the average surface temperature. While our average surface temperature is on the rise, there was a brief time after WWII when temperatures decreased.
Just after the war, industry kicked into full swing again and there were a large concentration of sulphates ejected into the atmosphere. Unlike CO2, sulphates reflect the sun light. As such, they have a cooling effect.
During the show, I had said that if you mix sulphates with water, you'd get sulphuric acid. This is not true. However, there have been many medical studies that show sulphates mixed into water supply have adverse effects on human intestinal tracts. It's still bad-news stuff.
Clean air acts were introduced globally from the 1970s. After this, the levels of sulphates in the atmosphere fell and the warming effects of the greenhouse gases took over.
There is no doubt about it. Humans have disrupted the natural balance of the Earth's environment.
In 2015, countries around the world met in Paris to devise a strategy to minimise our influence. It was agreed to reduce polluting activities and attempt to keep global temperatures to less than a 2°C increase compared to the pre-industrial levels.
There are some out there who believe that this will not be enough to help stabilise the Earth's environment. There are some who believe that we have already passed the tipping point and there is nothing to be done. However, I refuse to fall prey to that line of thinking. I refuse to give up on this fight. However, which of the ideas out there will actually work?
Like I said, while the science is real, the solutions are far from simple.
In a future episode (and blog post), Jessie Sanders and I intend to discuss some of the strategies that have been proposed to combat climate change and global warming. Some strategies, such as the electric car, have promise. Others, like killing all the cows, are just plain crazy talk.