Human-caused global warming theory shaky
The primary evidence linking human activity to global warming is getting weaker every year. There should have been about +0.4°C of surface warming since 1998 brought on by an accelerating rise in CO2 levels, according to IPCC models. There hasn’t been.
It’s a big deal because the IPCC says earth’s temperature has risen only +0.85°C since 1880. The lost heat is almost half that much. The urgency to curb CO2 emissions is to prevent a +2° or greater earth temperature rise that the IPCC says may cause dangerous, irreversible climate change.
Science now shows with 95 percent certainty that human activity is the dominant cause of observed warming since the mid-20th century
– Forward, IPCC Fifth Assessment Report (AR5), 9/27/2013
The most important new IPCC finding strengthens that human activity became the driving force behind climate change after 1950.
However, the weakness of the theory is clearly shown in the above graph plotting data collected since 1950. It does something the IPCC doesn’t do. It overlays the IPCC’s two most fundamental scientific data sets:
- Global air-sea temperature (HadCRUT4)
- NOAA atmospheric CO2 (Mauna Loa)
Together, these two data sets form the centerpiece for the argument that human-caused global warming is driving climate change. Both are prominently displayed in separate graphs at the start of the latest 2000-page IPCC AR5 report establishing the scientific foundation for the theory of anthropomorphic global warming (AGW).
Compare measurements to theory
The widening disconnect between human carbon dioxide emissions and global surface temperature is so great that the IPCC coined a new term to describe it: “hiatus”.
HadCRUT4 is the newest air-sea temperature database that the IPCC uses for its conclusions. HadCRUT4 combines two distinct types of temperatures. One is the global sea surface temperature database maintained by England’s Hadley Center. The other is a grand collection of all the world’s national weather service land-based temperature records put together by the Climate Research Unit of the University of East Anglia, also in England.
The second major data set used by the IPCC is NOAA’s measurements of atmospheric carbon dioxide levels made high atop Hawaii’s Mauna Loa volcano since 1958. CO2 is the primary greenhouse gas that drives global warming, according to the IPCC. It’s the green squiggly curve shown on the graph. It’s squiggly because of annual absorption and release of carbon dioxide within natural, seasonally-driven “carbon sinks”.
The graph shows that AGW theory matched up exceptionally well with observed temperature rise until the late 1990s. After that, observation and theory parted ways.
HadCRUT4 and carbon dioxide data above show:
- Global temperatures declined -0.1°C from 1950 to 1977
- Global temperature rise matches very well to CO2 rise from 1977 to 1998
- Global temperatures rose +0.5°C from 1977 to 1998
- Global temperatures have dipped very slightly since 1998
- CO2 has risen at an accelerating pace since first measured in 1958
- CO2 has risen fastest since 2001
The graph shows if the temperature-to-CO2 match from 1977 to 1998 had continued then the earth’s temperature today would be fully +0.4°C warmer than measured. That is a huge discrepancy. Ironically, that difference is nearly enough to prove mathematically there is a 95 percent probability that global warming is not human-caused!
The IPCC doesn’t mention that. Instead, it attributes the “hiatus” to volcanic eruptions, low sunspot activity and La Niña events. La Niña happens when sea surface temperatures drop more than -0.5°C below average. The IPCC doesn’t attribute any warming to the El Niño events of the 1980s and 90s. El Niño is when sea surface temperatures are more than +0.5°C above average.
The latest studies attribute the “hiatus” in atmospheric warming to heat absorption into the deep oceans below 2,300 feet. Those studies say the earth is still warming, but that the heat is hidden where we can’t feel it.
Don’t confuse North American’s current bitter cold with a change in climate. It’s not. It’s just weather. It’s a cold North American winter; nothing more.
Earth’s overall temperature remains at or near its highest levels since the Medieval Warm Period some 800 years ago.
On the other hand, human-caused global warming that was so very convincing in the data in the 1990s may not be the cause of earth’s high temperatures after all. With each passing year that CO2 continues its rapid rise while earth’s surface temperature doesn’t rise further erodes the foundation of AGW theory.
AGW proponents have resorted to a variety of natural causes to explain the “hiatus”. Among them are volcanic eruptions, weak sunspot activity, La Niña events and/or absorption of heat into the deep oceans.
After-the-fact explanations don’t work. They evoke all kinds of questions:
- Why aren’t the alternative explanations already accounted for?
- Why did IPCC models fail to predict the “hiatus”?
- Why are IPCC models off by 0.4°C?
- How come +0.5°C of +0.85°C rise since 1880 occurred in just 20 years?
- Why then did temperature rise suddenly stop after that 20 years?
- Can IPCC assessment reports be trusted?
- Are IPCC predictions about extreme weather reliable?
The IPCC has been warning us about global warming for decades for good reason. From 1977 to 1998 science pointed squarely at human carbon dioxide emissions as the cause of global warming.
Since then, though, the tide of science has turned away from AGW theory. Earth’s temperature so far this century has not risen at all. At its current decadal pace the earth will be the same temperature or cooler in the year 2100.
The theory of human-caused global warming is far weaker today than it was in the year 2000. The proof is in the graph!