Many (most?) of us at least occasionally confuse scientific facts with scientific assumptions and/or scientific falsehoods.
Even reading something in a science textbook, such as the textbooks pictured below, doesn't make something a scientific fact.
To help make the distinction between them clear, in the next section I provide one example of each of the three, regarding the planet Earth.
One Example of Each
Scientific Fact: The Earth is a globe that revolves around the sun. Observations by astronomers, astronauts, satellites, etc., offer corroboration for this. It’s an accepted fact. However, to complicate things, even facts are subject to debate. The Flat Earth Society[1] offers some evidence to dispute the Earth being a globe on its website.
Scientific Assumption: The Earth is billions of years old. You can call this a hypothesis, or even a theory, that is well supported by available evidence. However, there is inadequate proof at the present time to call it a fact. Quality human records only go back centuries, or at best thousands of years. Any theory about time before then is based on assumptions about constants, constant changes, etc. And I’m ignoring the possibility of time travel to keep it simple. A key method used to date the Earth at over 4 billion years old is radiometric dating of rocks based on those assumptions of constant changes, as reported by articles on LiveScience,[2] Space,[3] and other places. What if those constants aren’t really constant over billions of years?
Scientific Falsehood: The Earth is currently the
hottest it’s ever been. Reputable scientists all consider that totally false,
despite what you may read in news reports. Scientists actually believe the
opposite. The scientific assumption is that the Earth was at its hottest in its
early days, molten, as reported on Climate[4] and
numerous other website articles. Scientists feel that the Earth has generally
been cooling ever since, though there have been ups and downs. Furthermore, our
planet is expected to continue to cool in the upcoming millions and billions of
years, assuming the planet continues to exist. A 2022 WeatherChannel website[5] article even
states that “Earth’s interior is cooling faster than expected.”
One More Example of Each
I hope the above three illustrations help make the distinction between scientific facts, assumptions, and falsehoods clearer. I’ll provide one more example of each, regarding the Earth’s temperature.
Scientific Fact: The Earth has generally been warming since the Industrial Revolution in the late 1800s. Scientists have fairly accurate records of many temperatures on Earth for the last century or two. They show a fairly consistent warming trend since the late 1800s with a few exceptions such as a cooling period in the 1970s. A NASA[6] article states that “Air temperatures on Earth have been rising since the Industrial Revolution.”
Scientific Assumption: The Earth’s warming in the last century or two is due to human activities such as the Industrial Revolution. The NASA[6] article cited earlier notes that “the preponderance of evidence indicates that human activities . . . are mostly responsible.” Yes, there’s strong evidence to support human causation. But it’s impossible to totally account for all other factors to make it certain that humanity’s Industrial Revolution is the cause. Other factors could be contributing in ways we don’t know about yet.
Scientific Falsehood: If we don’t make changes, the Earth will continue growing hotter and hotter. As mentioned earlier, there’s an expected general cooling trend in geologic terms of millions of years.
What Will Happen to Earth's Temperatures in Coming Decades and Centuries?
The short answer is that humans don't know. But the heating of the Earth may not continue in the shorter term of decades and centuries. Effects on rainfall, plant growth, etc., of the current increases in temperature projected over the future are subjective. A 2016 NASA[7] article noted that “for now” global warming is benefitting plant growth.
That NASA article referenced a "study published in the journal Nature Climate Change." The Nature Climate Change journal[8] article states that the study found that "during 1982-2009" that greening increased ". . . .over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing. . . ."
Scientists don’t know yet what all the long-term effects will be.
One factor that may impact things is that humans will likely greatly reduce using fossil fuels either voluntarily or due to declining supply over the next century.
One Natural Occurrence That Greatly Affected Climate
Remember that unexpected things like earthquakes, volcano eruptions, etc., can impact our environment in ways that surprise scientists. For example, a volcanic eruption in the early 1800s led to such massive volcanic debris worldwide that 1816 became known as the year without a summer in some areas, with extremely cold temperatures.
One of the numerous articles about this volcanic eruption is on the United States National Park Service website.[9] That article states “the eruption of Mount Tambora in Indonesia in 1815 triggered a change in the global climate.” The article goes on to state, “The cloud blocked sunlight from reaching the earth and changed the global climate by 2-7 degrees Fahrenheit." The article also states, "in 1816, summer never came to the New England states."
Let’s Seek to Be Critical Readers, Listeners, and Viewers
I remember decades ago being urged to use plastic bags instead of paper ones to save trees. I sought to do so. Then I was urged to use recyclable ones instead of plastic to reduce oil consumption and plastic waste in the ocean. Then during COVID-19 some urged us to avoid using reusable bags to help reduce the spread of disease.
Changes often lead to unforeseen consequences. Solar energy is touted as clean energy. I'm glad its use is increasing. But many minerals must be mined from the ground to produce solar panels. High winds and storms can damage solar panels. Furthermore, large scale conversion of the sun’s energy to electricity via solar power may lead to unforeseen consequences we lack knowledge of yet.
Let’s seek to be critical readers who don’t always accept the latest fad or “scientific fact” as fact without seeking to think for ourselves logically.[1] The Flat Earth Society website; webpage accessed October 17, 2023; https://theflatearthsociety.org/home/index.php/about-the-society/faq
[2] Freedman, Ethan; “How do we know how old Earth is?”; LiveScience.com; April 15, 2023; webpage accessed October 17, 2023; https://www.livescience.com/planet-earth/how-do-we-know-how-old-earth-is
[3] Tillman, Nola Taylor; “How old is Earth?”; Space.com; August 20, 2021; webpage accessed October 17, 2023; https://www.space.com/24854-how-old-is-earth.html
[4] Scott, Michon and Lindsey, Rebecca; “What’s the hottest Earth’s ever been?”; Climate.gov; June 18, 2020, but first published in August 2014; webpage viewed October 17, 2023; https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been#:~:text=Because%20no%20rocks%20on%20Earth,Kelvin%20(3%2C680%C2%B0F).
[6] “World of Change: Global Temperatures”; NASA.gov; webpage accessed October 17,
2023;
[7] Reiny, Samson; “CO2 is making Earth greener—for now”; NASA; April 26, 2016;
webpage accessed October 17, 2023 and again October 18, 2023;
[8] Zhu, Z., Piao, S., Myneni, R. et al.; "Greening of the Earth and its drivers"; Nature Climate Change, 6, 791-795 (2016); April 25, 2016; webpage accessed October 18, 2023; https://www.nature.com/articles/nclimate3004#citeas
[9] “1816 – The Year Without Summer”; National Park Service website; last updated April 4th, 2023; webpage accessed October 17, 2023; https://www.nps.gov/articles/000/1816-the-year-without-summer.htm#:~:text=1816%2C%20also%20known%20as%20the,change%20in%20the%20global%20climate.
