The Science of Climate Change

By Ryan Allis

First, let’s start with the science of climate change.

1. When you have higher carbon dioxide (CO2) output, the amount of carbon dioxide in the atmosphere goes up.
2. When the amount of CO2 in the atmosphere rises, heat gets trapped.
3. When heat gets trapped in the atmosphere, the surface temperate rises.
4. When the surface temperature rises, ice melts and sea levels rise and weather patterns become more extreme.

Next, let’s look at the amount of carbon dioxide in our atmosphere over the past 800,000 years.

You can see that in general there is a natural system that regulates carbon dioxide ppm between 200 and 300. Carbon dioxide parts per million (CO2 PPM) have increased from 293 back in 1900 to 400 by 2013. Let’s zoom in and look at the amount of CO2 in the atmosphere since 1800 as well as the annual temperature to see the correlation between CO2 and temperature.

The relationship between higher carbon dioxide in the atmosphere and higher temperature is clear.

The deniers of climate change tend to use the same trick: They only look at the change in temperature from 1995-2013 and conclude that there’s not a correlation between CO2 and temperature. However, if you look at the data going back to 1960 and especially going back to 1880 there is a clear relationship.

Finally, take a look at the amount of carbon dioxide emitted into the atmosphere each year in the below chart, growing from 12 Gigatons in 1965 to 35 Gigatons in 2012. As we’ve emitted more CO2, the concentration of CO2 in the atmosphere has increased as has the surface temperature. The solution is clear—greatly reduce the amount of CO2 we emit into the atmosphere.

More CO2 from humans leads to more CO2 in atmosphere, which leads to heat trapped in the atmosphere, which leads to higher surface temperatures, which leads to an increase in sea levels, global changes in climate that displace populations, and extreme weather events.

According to a 2010 paper published in The Proceedings of the National Academy of Sciences in the United States, 97% of American Climate Scientists believe that the recent increase in carbon dioxide and global temperatures is caused by humans.

So what is the cause of CO2 and greenhouse gas pollution? The primary cause is the use of fossil fuels like coal, oil, and natural gas. The primary solution is moving to an economy driven by clean energy and not fossil fuels as quickly as possible.

Wake Up, World

The Intergovernmental Panel on Climate Change shared in their Fourth Assessment Report in 2007 that we’re on track for global surface temperatures will increase another 2 to 4.4°C which is 3.4° to 7.9°F during the 21st century.

So what would happen if our average surface temperatures increased by the midpoint of that range (3°C)?

Here’s a descriptive example of some of things that an organization called Climate Code Red has described as likely to happen if we see a 3°C increase by 2100:

“In the Pliocene, 3 million years ago, temperatures were 3°C  higher than our pre-industrial levels. The northern hemisphere was free of glaciers and ice sheets, beech trees grew in the Transantarctic Mountains and sea levels were 25 meters higher. ” – Climate Code Redd

Let’s take a look at another quote:

“Between 2° and 3°C of an increase, the Amazon rainforest, whose plants produce 10% of the world’s photosynthesis and have no evolved resistance to fire, may turn to savannah as drought and mega fires first destroyed the rainforest, turning trees back into carbon dioxide as they burn or rot and decompose.” – Climate Code Red

A systemic effect is one in which increased carbon dioxide increases the temperature and leads to a secondary ecological effect, which then creates more carbon dioxide, which then increases the temperature further, accelerating the cycle of warming and the damage to our planet.

Another systemic effect may occur in Siberian permafrost. Climate Code Red says, “As the Arctic continues to warm, melting permafrost in the boreal forest and further north in the arctic tundra is now starting to melt, triggering the release of methane, the greenhouse gas 20 times more powerful than carbon dioxide, from thick layers of thawing peat.”

The writer Ezra Klein says,

“There are thousands of gigatons of methane beneath the seas comparable to the amount of carbon contained in the earth’s coal deposits and as the Arctic waters warms some of this methane is likely to bubble up into the atmosphere.”

What would happen if sea levels rose by 15 feet? That would mean that Bangladesh would be under water; more than a third of Florida, under water; one-fifth of New York City, under water. Can we really accept a world in which these amazing populations—these amazing places—are under water? I don’t think so.

I have to say that much of the current debate does not recognize the true gravity and costs of the situation of additional carbon dioxide and current policy does not appropriately require carbon polluters to pay for their damage.

While scientists are aware of the critical correlation between higher carbon dioxide output and faster increase in temperature, many people just simply are not yet aware of what is likely to happen if we don’t quickly shift to renewable energy and reduce our carbon output. You can help out by sharing what you know with others.

If we don’t reduce our carbon output quickly, increased temperatures on Earth will will threaten our very civilization and create a destabilized world in which people don’t have access to their basic needs.

Moving to Clean Energy Quickly is Essential to Our Survival

Right now we are at 400 carbon dioxide ppm as of 2013. Where we stabilize that number will directly affect the amount of temperature increase and will drastically affect our children’s futures. Here’s a chart that shows the correlation between where we end up stabilizing the carbon ppm from the 400 we are today to where it will be in the future, and then in red the expected increase in degrees centigrade of temperature on the surface of the planet.

If we simply stay where we are today, it’s expected that it will increase about 1.5 °C by the end of this century. However, if we go up to 550 ppm, we’re looking at a little over 2° to 2.2°C.

Right now, if we do nothing, we’re on track for about 800 parts per million by 2100 if we continue our current industrial production of carbon dioxide and current use of fossil fuels. At that amount of carbon dioxide in the atmosphere, we might be expecting a 4°C increase in global temperatures (about 10 or 11°F). If that happens, we might see sea levels rise 25, 35, 40 feet. And there are so many connected ecological systems that we might actually end up much worse off than we are today and have a truly destabilized world. It is so critically important that we as a society figure out how to level off our carbon output below 500 ppm.

There are many scientists (and the entire 350.org movement) that says we actually need to end up under where we’re at today, under 400 ppm—and they may in fact end up being right. But from all the research I’ve seen and the scientists I’ve spoken to about this topic, we absolutely have to ensure that we as a society never go above 500 ppm of carbon dioxide.

 The low emission scenario that’s being considered would take us to that 550 ppm. Even this level of carbon PPM is unacceptable. We must move to a world of clean, renewable energy quickly.

For Further Reading on the reality of Climate Change:

• Skeptical Science
• George Lakoff’s article on systemic causation and climate change
• The Consensus Project

To learn more about what you can do to help, see Moving to a Clean Energy Economy.