Muutamia lainauksia Elokuulta 2019: (Ilmakehätieteiden prof. James Marshall Shepherd / NASA)
”As a climate scientist, I hear my share of myths about what is causing climate change or why it is a ”hoax.” I call them ”zombie theories” because they just will not die.
They persist in blogs, certain networks, and social media like zombies long after scientists have killed them off.
I debunked 20 of them in a previous article in Forbes. The ”sun and its variability” is one that makes the rounds. I am pretty sure I’ve had to spray ”climate science repellent” on that nagging ”mosquito” numerous times. This week I heard of a variation of this myth involving cosmic rays. Here is a science-based debunking of the solar-cosmic ray myth.”
”I won’t spend time highlighting any particular zombie theory about the Sun or cosmic rays. It is more useful to ”cut to the chase” on why the Sun doesn’t explain climate warming. The graphic below from a NASA climate website is the basis for the discussion. Solar energy is a very important part of our weather-climate system, but I find that some people don’t have a clear understanding of its role.”
”There is misconception that because we feel heat from the Sun and see it in the sky it represents how Earth’s surface is warmed at all times. It is actually far more complicated.”
”The Earth has an atmosphere with relatively small amounts of greenhouse gases like carbon dioxide, methane, and water vapor. However, don’t be filled by ”relatively small” because they are important. Colorado State University professor Scott Denning often says, ”We survive every night because of the Greenhouse Effect.” His point is that without the system of gases absorbing and re-emitting long wave radiation (heat) it would be too cold to survive. The shortwave radiation from the Sun is just part of the story (read more at this link at Forbes on how the Greenhouse Effect actually works).”
Graph 1. The energy from the Sun varies, and the 11-year sunspot cycle is a primary driver. According to a NASA website
”The total solar irradiance (TSI), improperly called “solar constant” until a few years ago, has been found to change about 0.1% in an 11-year solar sunspot activity. The current most accurate TSI values from the Total Irradiance Monitor (TIM) on NASA’s Solar Radiation and Climate Experiment ( SORCE ) is 1360.8 ± 0.5 Watts per meter squared during the 2008 solar minimum as compared to previous estimates of 1365.4 ± 1.3 W/m2 established in the 1990s.”
”This variation in solar energy is well known but doesn’t explain global temperature trends. NASA’s Global Climate Change website points out two smoking guns that debunk the overused ”it’s the sun” myth:”
”One of the “smoking guns” that tells us the Sun is not causing global warming comes from looking at the amount of the Sun’s energy that hits the top of the atmosphere. Since 1978, scientists have been tracking this using sensors on satellites and what they tell us is that there has been no upward trend in the amount of the Sun’s energy reaching Earth.”
”The other smoking gun is related to where the warming is taking place. The NASA website makes the point that ”if the Sun were responsible for global warming, we would expect to see warming throughout all layers of the atmosphere, from the surface all the way up to the upper atmosphere (stratosphere).” In reality, warming is being observed at the surface, but there is cooling in the stratospheric region. To anyone that has studied climatology and not astrophysics, this is a ”clear as a bell” signal that warming is related to greenhouse gases in the troposphere rather than the sun getting ”hotter” or other hypotheses. Dr. Jeff Masters does a ”masterful” job explaining why this happens at Weather Underground.
The galactic cosmic rays (GCRs) myth is our next ”debunk” target. It argues that GCRSs ”seed” clouds so if there are fewer cosmic rays then there will be less global cloud cover to reflect the Sun’s energy. The Skeptical Science website, an excellent scientist-run effort, debunks climate myths. Here’s what it says about the cosmic ray theory:”
Graph 2. Second-order polynomial fit
Huom! Merkittävä yhdenmukaisuus graafien 1 ja 2 välillä!
”The body of scientific research has determined that GCRs are actually not very effective at seeding clouds. However, the hypothesis is also disproven just by examining the data. Over the past five decades, the number of GCRs reaching Earth has increased, and in recent years reached record high numbers. This means that if the GCR-warming hypothesis is correct, this increase in GCRs should actually be causing global cooling over the past five decades, and particularly cold temperatures in recent years. On the contrary, while GCRs are up, global temperatures are also way up, and temperatures in recent years reached record highs.”
”Even in a 2017 article on this topic, scientists admitted that there was quite a bit of speculation in this GCR theory.
I often use an the analogy of an apple pie. Apples are the most important ingredient in the pie though some random person might argue for cinnamon or sugar. In the climate system, this well-understood climate graphic illustrates that greenhouse gases are the most important ingredient in the climate radiative pie.”
Alla pari linkkiä prof. James Marshall Shepherd sivuille
Ja alla linkki joka osoittaa, mikä todella maapalloa lämmittää (avaa alla oleva linkki ja odota, sitten skrollaa esitystä vaiheittain alaspäin).