The Science of Climate Change: Are We There Yet?
Adventures in Sustainable Living Podcast
Episode 92
The Science of Climate Change: Are We There Yet?
As most of you may know by now the discussions and concerns about climate change are becoming increasingly serious. Additionally, recent surveys in the United States and United Kingdom reveal that approximately 75% of us are concerned about it.
But there is also rampant disinformation out there concerning climate change. All it takes is a few minutes of research and you can easily find articles that both confirm and deny that this is even happening. Consequently, while there remains to be a level of concern, most people are not sure what to believe.
In this episode I am going to separate fact from fiction and explain the science of climate change and decide if we are there yet.
Welcome back everyone to the Adventures in Sustainable Living Podcast. This is your host Patrick and this is E92 which is called The Science of Climate Change: Are We There Yet?
Before we get started I would like to remind everyone that if you would like to contact me with questions, comments, or even suggestions of podcast topics of particular interest, then please feel free to contact me at [email protected]. Repeat.
So, that said, let’s dive right into this weeks topic concerning the science of climate change.
First of all you must know that the shear scope of this topic, as well as the volume of misinformation concerning climate change makes makes it very difficult to find the truth. But what I want to do here is hit the highlights with the end result being a basic understanding of what exactly is going on and why. As you likely know, I tend to be a pragmatic person. If someone tells me something is true or false, I want to see the science and the data behind it in order to substantiate the claim.
Furthermore, this is a complicated topic. Additionally the climate of our planet is complex and even chaotic. This widely used and accepted term of “global warming” is truly an over simplification of a highly complicated global process. But, I am going to attempt to to answer the following questions.
-Is climate change really happening and do scientist actually agree?
-Are there other natural processes that could be causing these changes?
-Is the climate change we are seeing just a natural part of our planet’s warming and cooling cycles?
-Does the natural production of greenhouse gases have some effect on climate change?
-If our planet is truly warming due to human activity, how do we know that?
-Should we be concerned that the planet has warmed by 2 degrees Fahrenheit over the past 200 years?
-Can we do something about it?
So, let’s get right down to it because we have a lot to cover. But let’s first talk about the evolution of the scientific thought process of global warming.
In 1824 Joseph Fourier calculated that a planet the size of the Earth at our distance from the sun ought to be a lot colder. He suggested that something in the atmosphere must be acting as an insulating blanket. In 1856 and American scientist Eunice Foote showed that carbon dioxide and water vapor in the Earth’s atmosphere trap escaping infrared radiation, meaning heat. IN the 1860s John Tyndall recognized recognized the Earth’s natural greenhouse effect and made the suggestion that even slight changes in atmospheric composition could bring about variations in the climate.
In 1896 a Swedish scientist names Svante Arrhenius published the first seminal paper on climate change. He predicted that changes in atmospheric carbon dioxide levels could cause substantial changes in Earth’s surface temperature through the greenhouse effect. Then in 1938 Guy Callendar connected carbon dioxide increases in the Earth’s atmosphere to global warming.
So, the bottom line is that in the mid-19th century scientists demonstrated the ability of carbon dioxide and other gases to trap heat. Many of the instruments used by NASA to study the Earth’s climate focus on how these gases affect the movement of infrared radiation through the atmosphere. From the study of the impact of the accumulation of these gases, there is now no question that an increase in greenhouse gases causes a warming affect on the planet.
Additionally there are a number of other scientific observations which offer some very compelling evidence. And this data is credited to the NASA website Global Climate Change, Vital Signs of the Planet:
Global Temperature is Rising: The Earth’s average surface temperature has risen by 1 Deg Celsius, or about 2 degrees Fahrenheit since the lat 19th century. Most of that warming has occurred in the last 40 years. This warming is largely due to increase CO2 levels in the atmosphere
The Oceans are Warming: Our planets stores about 90% of extra energy in the oceans. The top 100 meters, about 328 feet, has warmed by 0.33 degrees Celsius, or about 0.6 degrees Fahrenheit.
Snow Covering is Decreasing: NASA satellites observations show that snow covering in the Northern hemisphere has declined over the past 5 decades and snow is melting earlier.
Glaciers are Retreating: All around the planet glaciers are retreating
Ice Sheets Are Retreating: Greenland lost about 279 billion tons of ice per year between 1993 and 2019. Antartica lost approximately 148 billion tons of ice per year.
Sea Levels are Rising: And finally global sea levels have risen about 20 cm, or approximately 8 inches, over the last 100 years. However, the rate over the last two decades have doubled.
Natural Causes of Climate Change
But, despite this evidence, some people are going to argue that this is nothing more than a natural shift in the Earth’s climate. So, that said, let’s jut take a few minutes to discuss some of the natural causes of changes in the Earth’s climate.
Fluctuations in the Earth’s climate has always been a part of this planet’s history. There are a several natural causes of these changes including volcanic eruptions, changes in ocean currents, changes in the Earth’s orbit, variations in solar energy, and some internal variability. So, let’s briefly discuss all of these because it is really very interesting. I just love it when I learn something new.
Volcanic eruptions mainly cause short term cooling. Clouds of dust and ash block out sunlight which causing cooling. But this only lasts about 3 months because ash particles are actually kind of heavy and they eventually fall back to Earth. However, volcanic debris also includes sulfur dioxide. This gas easily combines with water vapor in the atmosphere to for an aerosol These sulfate aerosols reflect light away from the Earth’s surface and can remain in the atmosphere for a year or more.
For example, the eruption of Mount Pinatubo in the Philippines in 1991 produced a cloud of ash that circled the globe several times. Its eruption caused global temperatures to drop by 0.5 Degrees Celsius and this cooling effect lasted nearly 3 years. In 1815 the eruption of Mount Tambora in Indonesia had such a cooling effect that 1816 was called the year without a summer. This is considered the most destructive eruption in the last 10,000 years.
Ocean currents: The oceans play a major role in the climate system for our planet. Now why ocean currents move the way they do is somewhat complicated but it goes something like this. Ocean currents are located at both the surface and in deep water below 300 meters (984 feet). These currents move water horizontally and vertically and this happens on both a local and a global scale. The ocean currents are interconnected and this produces global circulation system, often referred to as the global conveyer belt. This system is powered by wind, tides, the Earth’s rotation, the solar energy, and water density differences. Additionally the topography and shape of ocean basins and landmasses also influences ocean currents.
Now ocean water density varies depending on the temperature, salt content, and depth. This density difference is what contributes to this global circulation system. Cold deep ocean currents carry denser water from the poles and toward the Equator. Warm surface currents carry less dense water away from the Equator and toward the poles. This global circulation system plays a key role in regulating the climate. The ocean currents transport warm water and precipitation from the equator toward the poles and cold water from the poles and back toward the tropics. This regulates global climate by counteracting the uneven distribution of solar radiation that reaches the Earth’s surface.
Now it is interesting to note that the global circulation is on roughly a 1,000 year cycle. What that means is that it would take a single water molecule approximately 1,000 years to complete a full cycle around the globe.
Now, it is also interesting to note that during the last ice age, extreme shifts in climate about every 1,500 years was linked to changes in the ocean currents. And since the end of the last ice age, it is the warming effects that the ocean circulation has produced that resulted in the development of civilization in Europe and North America.
Earth orbital changes: Now one other natural occurrence that affects our climate is changes in the Earth’s orbit. But these changes are so gradual that it is only noticeable over thousands of years. Slow changes in the Earth’s orbit and how it is tilted relative to the perpendicular plane of that orbit leads to climatically important changes in the strength of the seasons, meaning warmer summers and colder winters or cooler summers and milder winters. But these mild changes can trigger changes in climate such as either the beginning or the end of ice ages. Our last ice age ended 12,000 years ago and the next cooling cycle may begin in about 30,000 years.
Solar variations: Obviously the sun is an important source of energy for our planet. Although the output of energy from the sun appears constant on a day-to-day basis, small changes in the output of energy from the sun over an extended period of time can result in climate change. Several scientific studies have demonstrated that variations in solar energy output has resulted in past climate changes. For example, the Little Ice Age that occurred between 1650 and 1850.
But it is worth noting that since 1750 the average amount of solar energy from the sun has remained relatively constant or increased only slightly. If global warming was caused by more solar activity we would be seeing increased temperatures in all layers of the atmosphere. But, that is not the case.
Internal variability: And lastly there are climate variations due to internal variability. This variability produces some changes in climate that have no obvious external influences and are associated with interactions within the climate itself.
For example, the El Nino-La Nina cycle. These cycles affect atmospheric circulation. El Nino increase global temperature and La Nina decreases it. This cycles tends to repeat itself on about every 5 years.
Another example is Arctic oscillation (AO). This is associated with changing patterns in air pressure in the Northern hemisphere. Some phases in AO brings warmer conditions to Europe and North America and other phases do the exact opposite. These cycles have little affect on global climate but can have significant effects on local and regional weather.
Natural Variations in Earth’s Climate
Now, there are five different things discussed above that can cause variations in climate and some of those can be fairly dramatic. But is the climate change we are now seeing the result of natural variations in the cycles in the Earth’s climate.
While it is true that Earth’s climate has changed throughout history, the current warming is happening at a rate not seen for 10,000 years. Furthermore, to address this question, researchers have examined geologic records such as tree rings, ice cores, corals and sediments that contain vital information about about prehistoric climates. This information is used to further extend our current climate record of 150 years. What this research shows is that the Earth’s temperature change was essentially flat for centuries but sharply increases over the last 150 years. Numerous studies reveal the same result. Our planet has not been this warm in well over 1,000 years.
But what about natural greenhouse gases?
The other common argument is that natural greenhouse gas production is causing the planet to warm instead of human activity.
What you have to understand is that it is the greenhouse effect that keeps us alive. Greenhouse gases such as water vapor and CO2 play an important function in keeping the planet warm. Without them the Earth would be far too cold and life would not exist.
The temperature of our planet is a function of the energy the Earth absorbs from the sun and the energy the Earth emits back into space as infrared radiation. But greenhouse gas molecules absorb some of that radiation, emits some of it back to the surface which in turn warms the planet. This whole process has been well understood for over 150 years.
Through various natural processes, greenhouse gas concentrations in our atmosphere can vary. For example, over millions of years, CO2 levels have changed depending on how much gas is emitted due to volcanic eruptions. Greenhouse gases are also released though other geological functions. But this occurs over hundreds to thousands of years as carbon cycles between the ocean, the soil, and the air.
Is This Really the Result of Human Activity?
But after taking all of these things into consideration, how do we actually know that global warming is the result of human activity?
Scientist have consistently looked at all the natural causes of climate change, as in the 5 factors discussed above. It is generally agreed that these natural causes of climate change have remained essentially stable in the last few centuries and could have had some modest effects on climate variation particularly before 1950. But these factors cannot account for the rapid rise in global temperature in the second half of the 20th century. The best explanation is the rapid increase in greenhouse gases as a result of human activity.
Well, there are several types of greenhouse gases. Of those, CO2 only comprises a small portion of the gases in our atmosphere. However CO2 has an enormous ability to trap heat before it escapes into space. During the Industrial Revolution people starting burning coal and other fossil fuels as a means of powering factories, automobiles, heating their homes, running steam engines and producing electricity. All of this human activity has added an enormous amount of CO2 to the atmosphere.
For approximately 800,000 years atmospheric CO2 concentrations have varied between 180 ppm during the ice ages and 280 ppm during warmer periods. In fact when scientist analyzed bubbles of air trapped in ancient ice pack, before 1750 the concentration of CO2 was approximately 280 ppm.
These concentrations began to rise slowly and reached 300 ppm around 1900. Once automobiles and electricity came into widespread use, CO2 levels increased to around 420 ppm. Additionally, the concentration of methane and nitrous oxide, which are two other important greenhouse gases released primarily due to agricultural activities, have spiked over the last 250 years.
Due to human activity, we are now emitting carbon much faster that what was being released 66 million years ago. The scientific community now agrees that the natural cause of climate variability can only account for a small amount of this warming trend. Furthermore, the odds of the current warming due to natural causes is less than 1 in 100,000.
And what scientists also know, is that water vapor is by far the most abundant greenhouse gas. Since our planet’s atmosphere is warming, it tends to hold more water vapor. That additional water vapor tends to further amplify the effects of warming.
In the mid 1800s, temperature measurements have been taken at weather stations and on ships. As technology advanced, surface temperatures were tracked with satellites and scientist began examining geologic data. All of this information tells the same story. Earth’s temperature has increased by 2.2 degrees Fahrenheit, or 1.2 degrees Celsius, since 1880. The largest change in temperature has occurred in the late 20th century.
Surface temperature on land has increased the most. Arctic temperatures have increased by 4 degrees Fahrenheit. But the increase in surface temperatures actually mask the enormous scale of the climate change. The oceans have actually absorbed 90% of the heat. Oceanic expedition and a huge network of floating instruments have collected data for over 60 years. Every single layer of the ocean is warming.
Arctic sea ice is disappearing, snow melts sooner, plants are flowering earlier, and even animals are moving to higher elevations and latitudes to find cooler temperatures. Droughts, floods, wildfires, and storms have become more extreme. The surprisingly accurate computer models put together by climate scientists long ago have now come true.
Why Should We Be Worried About 2 Degrees Fahrenheit?
Earth’s temperature has increased by 2.2 degrees Fahrenheit, or 1.2 degrees Celsius, since 1880. Now that does not seem as it it should be a concern. But while 2 degrees difference matters very little when it comes to local weather, it makes a huge difference when it comes to climate. You also have to realize that 2 degrees is the global average. Many areas of the world have warmed far greater than that.
As we have already seen, that is enough to melt sea ice, thaw the Arctic regions, raise sea levels, shift rain fall patterns around the world, change ecosystems, cause heat waves to last longer and become more extreme, and force animal populations into cooler habitats.
And what is interesting to note is that under the Paris Agreement, nations have agreed to take efforts to limit the warming to somewhere between 1.5 and 2 degrees Celsius, or 2.7 and 3.6 degrees Fahrenheit. And yet this range has enormous implications for life on Earth. The difference between 2.7 and 3.6 degrees Fahrenheit will mean the difference between the survival of numerous plant and animal species. It will make the difference in whether Arctic regions completely melt. It will determine how many millions of people suffer from water scarcity, crop failures, and have to give up their homes and migrate to due climate extremes. In other words, one degree can make a world of difference.
What Can We Do?
I hope by now this presentation has convinced you that climate change is real, it is happening now and it is here to stay. In fact, the changes that we see will not be reversed in the life time of most people alive today. Approximately 97% of climate scientist now agree on the existence of climate change and the cause to it. But, that being said, this planet’s climate future has not yet been decided. So, if that is true, what are our choices?
Well, we can actually do nothing. Although this is not a good choice. Previous climate change models produced by scientists have proven astoundingly accurate. It that continues to hold true, the worse case scenario is that we will be facing up to a 9 degree Fahrenheit, or about 5 degree Celsius, increase in average global temperature. Now just for the sake of having a reference to what a difference that could make, if our planet was 9 degrees cooler, we would essentially be plunged into another ice age.
Our other choice is to stick to the Paris Agreement and stay within a maximum warming of 1.5 to 2 degrees Celsius, which is about 2.7 to 3.6 degrees Fahrenheit. But as stated above, that may be bearable but it will still make the difference between species extinction, water scarcity, and massive climate migration by both animal and human populations. Extreme weather events and natural disaster will continue to worsen. We will face massive crop failures and a global food crisis. Climate change will be worsened by changes in the global conveyer belt and circulates the oceans.
This of course leads me to our third choice which is to halt and reverse climate change. Most scientific data now agrees that if we reached zero carbon emissions, our climate would actually stabilize. But if we reached carbon negativity, meaning we are removing more carbon from the atmosphere than what we are producing, we would actually be able to reverse the effects of climate change. But, as individuals how do we accomplish this.
Carbon Neutral Lifestyle
One of the first things you can do is work toward a carbon neutral lifestyle. This is where your consumer choices make a difference. Work toward going zero waste. Consider electrifying your home getting rid of gas appliances. Take that a step further, and get your energy from clean sources such as solar. Solar energy is by far the most abundant energy source on the planet. The amount of solar energy that falls on the planet in one hour equals the total annual energy consumption of everyone on the planet. Twenty days of sunshine can produce the same amount of energy than all the Earth’s coal, natural gas, and oil combined.
Do simple things such as reducing your food waste. As much as 40% of the food supply chain in the United States goes in the trash. This means that all the resources put into producing that food also goes to waste. And we already know that our agriculture activities are one of the greatest drivers of climate change.
Change the way you eat. Just simply reducing your meat consumption can make a significant difference. Make dairy products a treat in your life instead of a mainstay.
Leave you car at home. Walk or ride a bicycle for shorter trips. Reduce your commuting. Use public transportation. Limit your airline travel.
Make it your personal mission to learn as much as possible about a carbon neutral lifestyle.
Talk to other people
The next best thing you can do it to talk to other people. Share your knowledge and concerns. No one is going to act if they do not believe climate change is a concern and it will impact their life. One of the major challenges with American culture is that in many ways we are far removed from some of the worse effects of climate change. Consequently, most people do not see the need to act.
Speak up
The next most effective thing you can do is speak up. I will have to admit that the longer I have been producing this podcast, the more I learn, the more changes I make in my own life, the more vocal I become. In fact, sometimes people think I am a bit weird but I don’t care.
Additionally, it is easy these days to find groups of people that share your concerns. Get some support about your concerns. Take that group voice to your community, state, and local leaders. Start asking them some tough questions concerning what they are going to do about the biggest industry polluters. We have to do this because in the end, it is going to take action on a national and international level to solve this problem.
Environmental Restoration
Another important thing we can all do is to get involved in environmental restoration. There are plenty of groups around. Get on line and find a local group to work with. Not only will you be helping the environment, you will also spend some time in nature which will make you appreciate the very thing we are trying to save.
Summary
Admittedly climate change is a complicated topic. Furthermore there is a tremendous amount of disinformation out there that tends to confuse everyone to the point that on one is sure what to believe. I truly hope this presentation has convinced you that climate change is here and we are experiencing the effects of that on almost a daily basis.
Scientist have now understood the greenhouse effect for over 150 years. It is this greenhouse effect that keeps us alive and well on a warm planet when we are so far from the sun. But the problem is human activity is enhancing this natural greenhouse effect and our planet is warming up. We know humanity is responsible for this because CO2, methane and nitrous oxide levels in the atmosphere have spiked since the Industrial Revolution. The result of this is that global temperatures are rising, the oceans are warming, snow cover is decreasing, ice sheets are melting, glaciers are retreating, and sea levels are rising. Our planet is now warming faster than is has in thousands of years.
We also know that some of the natural causes of climate variation is not responsible for the warming trend that we are experiencing. The effects of volcanic eruptions are short term. The effects of global ocean currents on weather are on a 1,000 year cycles. Earth’s orbital changes happen on a geological time scale. Variations in solar activity have been stable for several centuries. Internal climate variability such as El Nino-El Nina cycles and Arctic Oscillation produces on temporary changes.
The last remaining factor is human activity. At this point in time 97 percent of climate scientist agree that human activity is the direct cause of the warming trend that we are now experiencing. Most of the world governments also agree. Thus the formation of the Paris Agreement. However, even that agreement has limitations because if the world sticks to the agreed maximum range of increased temperature we are still going to experience some devastating effects of climate change.
As individuals we truly cannot wait for the world governments to adjourn from their never ending board meeting in order to make effective changes especially when each and everyone of us can make changes starting today. We can start working toward a carbon neutral lifestyle. We can work toward zero waste. We can take advantage of renewable energy sources. We can talk with others about our concerns, we can speak up and take our concerns to community, state, and national leaders, and we can personally take part in environmental restoration. One of the biggest things we can do is make our own daily lives the perfect example of sustainability. By doing so we influence the behavior of others.
I truly hope that I have convinced you that we need to take action. We all need the courage to stand up and speak out. Our choices do in fact make changes. When we take action that is when we will see hope. You know, I a one of those unusual people that looks forward to a new adventure and loves a good challenge. Despite the fact that we are in a crisis of our own making, we can actually fix it. It is going to take commitment, strong action, and changing the most basic things in how we live. But what choice do we truly have? We just need to work together. Perhaps it is time we all become an activist because we should never underestimate the power of a small group of committed citizens.
And in closing, I would like to say that if you enjoy the episodes that I produce, then please take the time to leave me with a review. And also, please subscribe to the Adventures in Sustainable Living Podcast as well as my companion blog Off Grid Living News.
But, until next week, this is your host Patrick signing off. Always remember to live sustainably because this is how we build a better future.
Resources
How Do We Know Climate Changes is Real? , NASA
Heat Absorption By Atmospheric Gases, Eunice Foote
On Radiation Through the Earth’s Atmosphere, John Tyndall.
On the influence of carbonic acid (CO2) in the air upon the temperature of the ground, Professor Svante Arrhenius
Ocean Circulation Implicated in Past Abrupt Climate Changes
Anthropogenic Carbon Release Rates Unprecedented During the Past 66 Million Years
Patrick
