Q1: Is there a greenhouse effect?
A: Yes.All you have to do is sit in your car with the windows up on a sunny day to know this is true.
Q2: Does the greenhouse effect have an impact on planets?
A. Yes.If we didn't have certain gases in the atmosphere trapping infrared energy, our planet would be as cold as Mars. Too much and you get Venus, so hot it can melt lead. Interestingly, any gas with three or more atoms creates a greenhouse effect. (Source: American Chemical Society). So greenhouse gases include carbon dioxide (CO2), methane (CH4), and sulphur hexafluoride (SF6, that was for a time in Nike Air Jordans). Even water vapor (H2O) can act as a greenhouse gas.
Roughly 98% of our atmosphere is nitrogen and oxygen with only two atoms each so they're not greenhouse gases (N2 at 78% and O2 at 21%) which leaves only about 1% for all the other gases, mostly argon. So it's a teeny, tiny percentage of the gases that keep our climate stable. It doesn't take a lot to throw that out of balance. It's not like adding another cup of tomato sauce to your chili; it's more like adding an extra cup of jalapeño chili powder to the recipe. Concentrations matter.
Q3: Have humans been increasing the amount of greenhouse gases in the atmosphere?
A: Yes.Scientists have been monitoring the rise in CO2 at the Mauna Loa Observatory since 1958. Since pre-industrial levels, we have increased the CO2 in the atmosphere by over 40% (from about 280 ppm to over 400 now.) This trend follows the same path as the use of fossil fuels. It's really quite simple. If we take hydrocarbons from their ancient burial place in the earth and burn them, releasing them to the atmosphere at a much greater rate than Nature can put them back, they build up.
A lot of the CO2 has been absorbed by the oceans, which is making the ocean measurably more acidic. But methane represents about 40 percent to the heat-trapping effect of all human-produced greenhouse gases in the atmosphere. Methane comes from natural gas (much of it leaking out of pipes) and also from rotting organic matter (like food in landfills and thawing permafrost.)
Think of our planet as a box with a pipe of greenhouse gases coming in and a pipe going out. For most of the last 10,000 years, the size of the two pipes were balanced, the same amount of greenhouse gases coming in and going out. Humans have not only increased the amount coming into the box with fossil fuels and other chemicals. We've also reduced the size of the pipe going out. For example, deforestation has reduced Nature's ability to take CO2 out of the air. Sometimes cycles make things progressively worse. For example, the oceans have absorbed a lot of human-made CO2 but as the ocean warms, it can't hold as much gas. (Think of your soda going flat on a warm day.) Or as sea ice melts, it reveals a darker ocean that absorbs more heat than the ice did, speeding up the rate of warming.
Q4: Will this have an effect?
A: Yes.We know from ice cores that CO2 levels map precisely against ancient temperature swings; more CO2 leads to a warmer global climate every time.
Any system is going to have a reaction to significantly different concentrations. Imagine increasing your fat intake by 40 percent or your body temperature. Exactly what will change where, by how much, by when are very complicated questions to answer. But continuing to add greenhouse gases to the atmosphere will clearly change the climate. According to the world's scientists, it already is. But you don't have to ask them. You can see spring coming sooner, glaciers retreating, and sea level rising.
What people typically don't understand
- Scientists only disagree about the details. My brother was trained as a scientist and I'll tell you, they love to argue and poke holes in one another's theories. The disagreements around climate science tend to be about how the impacts will play out. But 97 percent of the world's climate scientists agree the climate is changing and that humans are the primary cause.
Imagine you take your child to a doctor because you've noticed some worrisome symptoms. The doctor tells you the treatment may cost some money and be inconvenient but without treatment, the disease is likely life-threatening. You go for a second opinion and a third. Eventually you see 100 doctors, 97 of them saying the same thing. But a couple doctors say, "Hey, she might grow out of it, take some Vitamin C and hope for the best." What do you do? Most people listen to the 97 doctors. That's where we are regarding the climate.
- Climate change (what many call global warming) can make some places colder at times. It's doing some odd things to weather patterns, bringing cold arctic air into the US at times. It's better to think of it as destabilizing the climate. Some people in cold climates welcome spring coming sooner. But we depend on a predictable climate: when to plant crops, when the rains will come, what weather we need to construct buildings to withstand, etc.
- The change may not be gradual. Think of your annoying little brother rocking the canoe. Most of the time, the canoe rights itself. But if he goes too far, you're suddenly in a different place. The difference is with the climate, there may be no easy way to get back to the previous state, to get back in the canoe.