Superfact 25: Global warming is happening. Or if you call it Climate Change or Climate Disruption is happening. And it is happening very fast. We also know that it is caused by us primarily as a result of our burning of fossil fuels. There is a long-standing scientific consensus on these two facts because the evidence is conclusive. Check the evidence below.
This is a long post. However, I summarized this somewhat complex issue in a post I hope is both comprehensive and easy to read at the same time. I believe you can learn a lot from reading it. Note in this post, Global Warming Is Happening And Is Caused By Us, I will use the terms climate change, climate disruption and global warming interchangeably, or nearly interchangeably. I am doing that on purpose.
A lot of people would like to dispute this fact. Including large segments of the public, politicians, and political organizations. I was once a so-called skeptic myself. However, climate scientists very rarely dispute this because of the large amount of compelling evidence. This is a good summary from NASA. We know it’s true, it is important, yet disputed, which makes it a super fact in my opinion.
Below I created a top 10 list of evidence for the fact that climate change / global warming is happening. As well as a top 10 list of evidence for the fact that we are the cause for it. Primarily because of our burning of fossil fuels.
Evidence that Global Warning is Happening
- (1) The temperature records collected by numerous organizations show that global warming is happening. Organizations such as NASA, NOAA, the Hadley Centre, the European Centre for Medium-Range Weather Forecasts, the Japanese Meteorological Agency, the World Meteorological Organization, and many more, use data from land-based weather stations, ocean buoys, satellite measurements, and other sources to monitor Earth’s climate. Comparison with the palaeoclimatological record shows that the rise in average global temperatures is extremely fast. This is the smoking gun. However, for those who question the data from all of these organizations there are other simpler types of evidence (see below).
- (2) Global sea levels has increased by 20–25 cm (8–10 in) since 1900, with half of that increase occurring since 1980. Sea level rise occurs from a combination of thermal expansion and the melting of land ice, both which happen as a result of warming. This sea level rise has been the fastest in “at least the last 3000 years”.
- (3) Arctic ice is melting. See the video from NASA below.
- (4) Glaciers are retreating.
- (5) The Antarctic ice sheet is losing ice at a rate of about 100–200 billion tons per year, which has increased in the past two decades.
- (6) Eco zones are generally shifting northward and to higher elevations, meaning that plant and animal habitats are moving towards cooler regions as temperatures rise in previously suitable areas.
- (7) Snow seasons are getting shorter
- (8) Extreme events are increasing in frequency showing that climate is changing
- (9) After extensive research and scientific debates in the past there is now a long-standing scientific consensus that Global Warming is happening. This is not physical evidence itself, but it does not an appeal to authority fallacy either. Think about it in terms of probability.
- (10) Old guys originating from northern climates like me, have noticed that the seasons are changing. Even if you dismiss all the evidence from NASA, NOAA, IPCC, and all the world’s meteorological institutions, and you claim that all the world’s climate scientists are all in a massive conspiracy, you cannot convince me of something that is contrary to what I can see with my own eyes.
Graphs and Videos Showing Global Warming
Confusion About Climate Change
Before continuing I would like to address a couple of issues that sometimes trip up people. And prevent them from learning about this topic.
The question “climate has always been changing, why would we be the cause now?”, is a good question. If asked honestly. However, it is a bad question if it is asked like a gotcha or a dismissive statement. In this case it is a bad question. Because the paleoclimatologists and the climate scientists, in other words the experts on past climate, are the ones telling us that the current climate change / global warming is caused by us, it is not “natural”. They obviously say that because they know something that the dismissive laymen don’t. All everyone needs is a tiny bit of reflection to realize that you’ve got something to learn from them.
Sometimes you come across people who have a hangup over the fact that we use a few different terms interchangeably, global warming, climate change, climate disruption, inadvertent climate modification, etc. The people who have a hangup about this jump to the incorrect conclusion that there is some sort of deception or backtrack going on. If I talk about my dog and my mini-Australian Shepherd, I am not confused or deceptive or backtracking anything. It is the same family member. Whether you call it global warming or climate change or something else is a distracting non-issue, a red herring if you will.
To add some information about it. Climate change has become the more popular term recently, but the terms climate change and inadvertent climate modification predates the term global warming, which became popular in the 1980’s largely because climate scientist James Hansen likes to use it. Climate change is a broader term since it could include global warming and global cooling, but in the current context, global warming is a good term as well since that is what is happening now.
One advantage of the term climate change is that the average warming trend is in itself not the major issue. The effects on the overall climate that warming has is the more important issue. You could say that you want some global warming when the weather is cold and it would make sense. But you don’t want the destruction of eco systems, oceanic and atmospheric circulation changes, sea level rise, worse storms, draughts, floods, wildfires, etc., that it causes.
Natural Causes of Climate Change
There are many different kinds of natural causes of climate change. Two billion years ago cyanobacteria developed a form of photosynthesis that absorbed carbon dioxide and emitted oxygen, as well as a way of extracting nitrogen using a process called nitrogen fixation. This made cyanobacteria extremely successful. One consequence of this was that the carbon dioxide was largely removed from the atmosphere, and the earth got very cold, but the oxygen that was now present in the atmosphere paved the way for the existence of multicellular life and animals. To find out more about this, read this book.
The planet changed but it took millions of years. The emergence of land plants did something similar. Examples of other slow-moving drivers of climate change are continental drift and the fact that the light from the sun has gotten 6% stronger over the last one billion years (0.006% per million years).
65 million years ago an asteroid struck earth, which caused earth’s climate to change, which is probably what killed the non-avian dinosaurs. Another example of a past climate change driver is unusual volcanic activity. Volcanoes emit greenhouse gases, such as carbon dioxide (CO₂) and water vapor, during eruptions.
However, their contribution to the total CO₂ emissions in modern times is very small compared to human activities. Annual volcanic CO₂ emissions are estimated to be around 200-500 million tons while humans add 37-40 billion tons, or 100 times as much. Therefore, it is unlikely that volcanoes contribute much to the current warming, but the fine sulfate aerosols emitted by volcanoes can cause a significant cooling effect for a few years.
One type of important type of climate forcing that’s been the cause behind the multiple ice ages that we’ve had over the last two million years are earth’s orbital cycles, or the Milankovitch cycles. There are three of them, orbital eccentricity, change in axial tilt, and axial precession. Could they explain the current warming? No, they can’t because we are currently in a cycle that should be cooling the planet. And it was until now. Below I have included a video from PBS that explains these orbital cycles.
There are also short-term solar irradiance cycles. There is an 11-year cycle and an 80-year cycle, but these correspond to small changes. The 11-year cycle corresponds to a temperature change of 0.05 degrees Celsius.
In addition, the Sun’s irradiance has been slightly decreasing over the past few decades. Changes in the sun’s irradiance cannot explain the sharp warming we are witnessing. As you’ve seen above, neither can volcanic activity nor any known orbital cycles, slow moving climate drivers such as continental drift cannot explain it and we did not get hit by an asteroid recently. However, what fits the bill almost perfectly is our greenhouse gas emissions.
This is a brief overview from MIT.
What Does Climate Models Say About Climate Change
Unlike weather, the climate is not particularly sensitive to initial conditions (chaos). For example, we can be pretty certain that July will be warmer than January in Minnesota. We use climate models to try to predict future climate. All climate models rely on the laws of thermodynamics. But they vary in regard to the different understandings of the best ways to incorporate those laws in a representation of all of Earth. They do not come up with identical results. But they all get the average temperature of each region of the world right.
In addition, the various old climate models from the 1990’s do a very good job of what has happened during the last 30 years. They aren’t perfect but they are useful and more importantly for our context they serve as powerful evidence that the current warming is caused by our emissions. You remove our emissions from the models and none of what we measure will happen. Climate models are therefore the smoking gun with respect to what is causing global warming, just like the temperature record is for the fact that it is happening in the first place.
Unfortunately, the climate models have been maligned and misrepresented by those who wish that the public do not pay attention to them. That’s why we need to mention additional types of evidence (see below).
Evidence that Global Warming is Caused by US
- (1) Climate models – as we have seen above, climate models are the smoking gun evidence that we humans are causing global warming / climate change. In addition, both simplistic and complex climate models show that 100% of global warming is caused by humans.
- (2) Greenhouse gases will make the planet warmer, and we are emitting a lot of them.
- (3) The upper troposphere is cooling, which shows that the heating is from greenhouse gases and not the sun or orbital cycles. To understand how the lower atmosphere is warming while the upper is cooling, think of the greenhouse gases as a blanket.
- (4) winters and nights are generally warming faster than other seasons and times of day due to the increased presence of greenhouse gases in the atmosphere, which trap heat more effectively during colder periods. This is considered a key indicator of human-induced climate change.
- (5) The speed of the warming, 0.31 degrees Fahrenheit per decade, or 0.17 degrees Celsius per decade is extremely fast. Known natural climate forcing tends to be slower.
- (6) Human activities is the only known explanation for the current global warming. One way that we know that the current warming is caused by human activity is because we are currently in a cycle that should be cooling the planet. The same is true for the sun’s irradiance. It is not volcanoes or any other known cause. See the section above called “Natural Causes of Climate Change”.
- (7) Isotope studies show that the origin of the greenhouse gases added to the atmosphere are from burning fossil fuels. This is referred to as the isotopic footprint.
- (8) The observed temperature rise mirrors industrialization.
- (9) More than 90% of excess heat from global warming is absorbed by the oceans, causing significant increases in ocean temperatures. Oceans absorb about a quarter of human CO₂ emissions, leading to lower pH levels. This is unprecedented in at least 26,000 years and is directly linked to anthropogenic CO₂. These effects have been carefully studied and observed.
- (10) Nearly all actively publishing climate scientists say humans are causing climate change. This is not physical evidence itself, but it does not appeal to authority fallacy either. Think about it in terms of probability.
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