Basic Climate Change Science (Q&A)

Originally written on August 9, 2013  

Updated on August 18, 2013 and September 28, 2013
Here is an overview of some basic climate change science in a Q&A format.
The questions I came up with are:

1. What is the greenhouse effect, and isn't it natural?
2. How do warming temperatures effect the earth?
3. How does climate change relate to the hole in the ozone layer?
4. Aren't some areas getting colder?
5. Isn't climate change a hoax (created by scientists to get more grant money)?

Scroll through my answers and please let me know if there are other general questions I have missed that you want an answer to.

1.  What is the greenhouse effect, and isn't it natural?
Yes, the greenhouse effect is a natural phenomenon in our atmosphere. Carbon dioxide (CO2) and other greenhouse gases in our atmosphere form a type of blanket at the top of our atmosphere. The sun's rays enter the atmosphere and warm up the earth. The natural CO2 in the atmosphere traps some of the heat in our atmosphere, and the excess heat is reflected back into space. This process keeps our atmosphere a comfortable temperature for life on earth.

Without the greenhouse effect life as we know it could not survive on earth. The problem is, humans have enhanced the natural greenhouse gas effect by adding extra CO2 into the atmosphere through the burning of fossil fuels--fuels like oil, coal, and gas that were locked underground for millenia. Humans burn fossil fuels for activities such as driving cars, heating and cooling homes and businesses, generating electricity, and other industrial processes.

The graphic below shows the natural greenhouse gas effect compared to the human enhanced greenhouse effect. This human enhanced greenhouse effect is responsible for global warming and it is leading to climate change.

source: US Natural Park Service

Here's another more fun and animated way of explaining the greenhouse effect:



The average annual temperature has been steadily increasing since the Industrial Revolution, along with CO2 levels. The temperature increase is shown in the NASA chart below (click on the link in the caption to see the interactive map). One degree Celsius may not seem like a lot, but it was only a 1-2 degree drop in temperature that created the Little Ice Age (source).

: 1em; margin-right: 1em;">The above is a screen shot of an interactive map produced by NASA.


2.  How do warming temperatures effect the earth?

A.  Sea Level Rise
So far our oceans have actually absorbed 90% of the excess heat trapped by anthropogenic CO2 (CO2 added into the atmosphere by human activities). This has delayed the warming of our atmosphere, but the air has warmed too. The warming of the oceans has caused sea level to rise (water expands when it is warm), making coastal areas at risk for flooding.

B.  Melting Polar Ice Caps
Warmer oceans and warmer air are melting of the polar ice caps (North Pole-Arctic, and the South Pole-Antarctica). The polar ice caps are great regulators of the global climate. Less ice at the poles means more heat is absorbed, instead of being reflected off the great white ice sheets back into space. When sheets of ice slide off land masses into the ocean this also contributes to sea level rise (like adding an ice cube to a cup of water makes the water rise)..

C.  Superstorms
Due to the warmer ocean and warmer masses of air there is more evaporation, and thus more water vapor in the atmosphere. Atmospheric humidity has increased by 4% in the last few decades. Storms, such as hurricanes, get their energy from warm ocean waters, which provide more power to storms. With more water vapor in the atmosphere these stronger storms are able to pick up more water vapor and then dump more precipitation on the area experiencing the storm. This is true of snow storms too, they pick up extra water vapor and then dump it as snow.

One analogy is: consider the atmosphere like a bathtub and the storm itself like the bathtub drain.  When you drain the bathtub you are draining water from the entire bathtub, not just the area directly over the drain. More water vapor in the atmosphere is like filling the tub even higher, so there is more water that can come out the drain.

D.  Floods
More large precipitation events mean we are more prone to see flooding during these events because they overwhelm rivers, streams and stormwater systems. Some areas of the world are seeing larger snowstorms, but the wamer atmosphere is causing temperatures to warm up more quickly in the spring. Therefore, the snow melts faster and we get more serious spring flooding events.

E.  Droughts and Fires
How can we get both wetter and drier? We are getting more large storms/rain/snow events, but fewer moderate or mild rain events. The increased heat in the atmosphere causes faster rates of evaporation. Water evaporates from soil even faster than it does from bodies of water so soils dry out extra fast. Without regular precipitation to replenish the soil things just get drier and drier. When forests and plains are drier they are more prone to wildfires that spread quickly throughout large areas.

F. Threats to plants, wildlife and agriculture
Our planet is like a "Goldilocks Planet" because of the unique composition of our atmosphere--not too hot, and not too cold. Plants and animals on earth adapted to this very specific environment over thousands of years. Predictable temperatures and weather allowed life to thrive. Changes in these systems make it harder for species to thrive due to changes in habitat, new distribution of diseases and pests, and loss of food sources. Plants and animals are unable to adapt to rapid changes in temperature and environment as quickly as it is happening now due to man-made climate change.

G. Ocean Acidification
CO2 reacts with ocean water and increases its acidity. This makes ocean water corrosive, which then makes it harder for corals to develop and grow, and makes it harder for other organisms with shells to produce shells, such as oysters. This has both food supply and economic impacts.



3.  How does climate change relate to the hole in the ozone layer?
The hole in the ozone layer is what allows more of the sun's harmful UV rays to enter the atmosphere. UV ray exposure causes skin cancer in humans, and other species. Climate change is caused by the buildup of CO2 and other greenhouse gases that trap heat that would have otherwise radiated back out into space.

The issue with the ozone layer is somewhat related to climate change. The hole in the ozone was caused by chloroflorocarbons (CFCs) being released into the atmosphere. CFCs were used as refrigerants until the 1989 Montreal Protocol began successfully phasing out these gases. CFCs were replaced by new chemicals that do not bind with the natural ozone in the upper atmosphere (thus depleting it and creating a hole for more dangerous UV rays to get through). The link between CFCs and climate change is that CFCs are also considered a greenhouse gas (heat trapping gas). CO2 is still a bigger concern than any other man-made greenhouse gases because it alone comprises more than half of all man-made greenhouse gas emissions.

Update: just today I saw an article that the hole in the ozone may in fact be warming air around Antarctica due to shifting winds (source).

4. Aren't some areas getting colder?
Global warming doesn't mean that there are no more cold days or no more big snow storms. Some scientists are finding that Europe could get colder (at least temporarily) due to the slowing of the Gulf Stream in the Atlantic ocean. The Gulf Stream is driven by wind and carries warm ocean water from the equator to the British Isles, making Europe 5 to 10 degrees warmer than it would be without the Gulf Stream (source). Influxes of cold water from the melting Arctic can slow the Gulf Stream leading to colder temperatures in Europe. Also, some areas may get more snow in winter due to the superstorm effect described above.

Global warming has also led to the destabilization of the jet stream. A weak jet stream allows cold Arctic air to escape and bring cold air to areas that have not traditionally seen cold temperatures, (source). It's like leaving the refrigerator door open and the cold air escapes to other parts of the house, (source).

 As scientists have learned more about the effects of man-made greenhouse gases in the atmosphere they have shifted to using the term "climate change," because it better describes the many effects it has. "Global weirding" is another term used since as the earth warms our weather patterns are shifting greatly.

The earth is a very dynamic system and scientists are learning more every day on how it works. Overall, the average global temperature is on the rise, and has been since the 1880s, just after the Industrial Revolution. Record-breaking cold temperatures are occurring far less often than record breaking heat events (source).


 5. Isn't climate change a hoax created by scientists to get more research grant money?
If this is what you believe even after reading about climate science I don't think there's anything I can tell you to change your mind. I will leave you with this from (source):

"Scientists are 95% certain that humans are the "dominant cause" of global warming since the 1950s."

Also consider the story of Richard Muller, a physics professor at UC Berkeley, and former climate skeptic, who was funded by the Koch brothers (quintessential climate change deniers) to study climate change research. After completing his study he now states that climate change is real and "humans are almost entirely the cause of climate change." (source).


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