Is Climate Change Real?

Temperatures have been rising for the last 40 years:
Global Temperatures from NOAA (US Gov't Agency in charge of weather prediction, who run the weather satellites)

Source: NOAA Climate at a Glance Website

There was warming due to increased GHG emissions until the early forties, after which air pollution, particularly sulfate particles from burning coal, built up in the atmosphere, resulting in a couple of decades of net cooling until envionmental reguluation reduced this pollution in the early seventies, after which warming resumed.

Consensus Among Scientists:

There is a very strong consensus among the experts.  There have been many surveys of climate scientists or of technical papers on climate science, some of them very extensive.  Here are some of the surveys with the level of consensus that they found:

  • Oreskes 2004 - 100%
  • Doran 2009 - 97%
  • Anderegg 2010 - 97%
  • Cook 2013 - 97%
  • Verheggen 2014 - 91%
  • Stenhouse 2014 - 93%
  • Carlton - 2015 - 97%

Usually, what happens is that if you start out with a broad survey of all technical people, you get a majority, and as you narrow the field down to people whose specialty is more and more relevant to climate science, the percentage agreeing goes up, until, when you get to actual climate scientists, the consensus is very high, and then if you get to climate scientists who have published recently, it's 97%.

Bear in mind that the consensus is on the statement "The Earth is warming and human emissions of greenhouse gases are the cause.". It goes no further than that! That 97% do not agree about exactly how bad it will or won't get in the future, and they certainly don't all necessarily agree with every word said in the 1,500 page UN IPCC Reports. It says nothing about the future, or what, if anything, should be done about the problem.

Some of these surveys are quite large. For example, a survey by John Cook looked at abstracts for 11,944 papers on the subject of climate change, of those, 66.4% expressed no opinion since climate scientists have other things to discuss (note that "no opinion" means that they did NOT express the opinion of uncertainty), while 32.6% supported the statement, 0.7% rejected the statement, and 0.3% expressed the opinion that they weren't sure. 32.6 / (32.6 + 0.7 + 0.3) is 97%.

CO2 Levels Since 1960
Click to Enlarge

CO2 Levels: Last 1,000 Years
Click to Enlarge

CO2 Levels: Last 800,000 Years
Click to Enlarge
Carbon Dioxide:

There's a lot of noise in the temperature data, but CO2 levels have been increasing at a very smooth rate, except for very predictable seasonal variation.

We have a very reliable record of CO2 levels from Greenland and Antarctic ice cores going back 800,000 years, and current levels are completely unprecedented over that time period. Bear in mind that homo sapiens has only been around for 300,000 years. So CO2 levels have never been this high in human history.

Before 800,000 ago we have geologic records that are much less precise. If you go back dozens of millions of years, for most of the planet's history, CO2 levels were many times higher than now, and temperature was too, with no ice anywhere on the planet -- none at the poles, and no glaciers in the mountains. Sea level was many dozens of feet higher than it is now.

During most of the planet's history, higher CO2 levels correlate very closely with higher temperatures in the long term.

Climate skeptics often point out that geologists say that there were some glaciers at a time when CO2 levels were an order of magnitude higher than now. This was about 450 million years ago -- 100 million years before the first reptiles. The sun was 5% dimmer at that time, and all that CO2 was the only thing keeping the planet from turning into a complete iceball.

The US Navy has done extensive research on what levels of CO2 submarine crews can tolerate, and they have decided it's best to keep levels in submarines below 1,000 ppm (parts per million). If we make no effort to curb emissions, we will reach levels of about 1,200 ppm by 2100, so we will be reaching the level at which people begin to feel uncomforable and human cognition begins to get impaired.

White Chuck Glacier, 1973

White Chuck Glacier, 2006

90% of the world's glaciers are retreating and 10% are advancing. Much of the world relies on seasonal melting of glaciers for their water supply, so as glaciers permanently recede, populations will be losing access to fresh water.
Estimated pH change, 1700's - 1990's
Click to Enlarge
Ocean Acidification:

Much of our CO2 emissions wind up dissolving in the ocean and forming acid, so the oceans have been becoming more acidic, which will have a significant impact on marine ecosystems. The oceans are naturally slightly alkaline, but from 1751 to 1996 the pH has declined from roughly 8.25 to 8.14, which translates to a 28% increase in the concentration of H+ ions in the water. Changing the acidity of the ocean will have a profound impact on many of the fundamental chemical reactions upon which life is based. The acidity of the ocean is currently changing faster than it has at any time in the last 55 million years. Ocean fishing is one of the human race's primary food sources.

Coral Bleaching:

Rising ocean temperatures have been bleaching and killing coral reefs in the ocean. It is expected that if we take no action to curb global warming, we will observe a near-wipeout of our coral reefs by the end of the century.
Skeptical Science Website:

If the reader is scientifically inclined, and wants to dive in to the details, the evidence is pretty overwhelming and with a little time, they can make up their mind on the technical merits of the case.  There is an excellent website,, where you can look up pretty much every major argument made by climate skeptics, and find rebuttals to them.  Usually, rebuttals are given at 3 levels: "Basic", "Intermediate", and "Advanced", depending on one's appetite for detail.  In addition, there is a conversation following that among very intelligent climate scientists (and an occasional climate skeptic) discussing things in even more detail than that.

Marc Morano
Famous Climate Skeptic
Climate Hustle:

Also, this group periodically shows the movie Climate Hustle, by nationally famous climate skeptic Marc Morano, who runs the Climate Depot website and authored The Politically Incorrect Guide to Climate Change. The movie makes many, many scientific arguments to back up his claim that global warming is not real, and we frequently stop the movie to comment on these arguments as they are made.