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Climate Denial #1 - Six Inaccurate Facts
I am going to dribble out “factoid” posts about climate denial. These are not intended for actual climate deniers. As I’ve written elsewhere, droning on about the data is not going to make a difference. It is for people I think of as “climate-aware” — to provide useful Information that might clarify things in your own mind. As usual, many thanks to Alina Goh. Here goes:
Inaccurate Fact #1: It’s the sun
Fact: In the last 35 years of global warming, the sun and climate have been going in opposite directions.
Solar irradiance is the output of light energy from the sun, measured at the Earth
Although global surface temperature (the red line) has been steadily increasing over time, solar irradiance (the yellow line) has decreased, cancelling out a possible correlation between current temperature increase and the sun’s influence
Additionally, if the sun were responsible for climate change, warming throughout all atmospheric layers would be expected. Instead, warming on the Earth’s surface and cooling in the stratosphere has been observed
This is consistent with buildup of greenhouse gases near the surface of the Earth, not by increased heat energy from the sun
Inaccurate Fact #2: Models are unreliable
Fact: Models successfully reproduce temperatures since 1900 globally, by land, in the air and the ocean.
Climate models have been proven as reliable climate predictors, and continue to grow more accurate as more data points are added to them
Scientists use hindcasting - testing a model’s accuracy in mapping out past events - to demonstrate the reliability of climate models
Despite minute uncertainties, 21st century climate models have been widely deemed reliable projections into the future, perhaps even more conservative in their predictions than what will actually occur
Inaccurate Fact #3: Climate sensitivity is low
Fact: Net positive feedback is confirmed by many different lines of evidence
Climate sensitivity is the globally averaged temperature change in response to a doubling of atmospheric CO2
Skeptics argue that the Earth’s climate sensitivity is so low that doubling atmospheric CO2 will result in less than 1 degree celsius of warming
However, net positive feedback has been confirmed using a variety of methods, including paleoclimate data, recent empirical data and generally accepted climate models
The converging conclusions of these different approaches makes a strong case for higher climate sensitivity
The IPCC estimated that climate sensitivity was likely to range from 1.5-4.5 degrees celsius, with a best estimate of 3 degrees celsius
Inaccurate Fact #4: Sea level rise is exaggerated
Fact: A variety of different measurements find steadily rising sea levels over the past century.
The graph shows that global mean sea level has steadily risen since 1870, accelerating in the past several decades
Data from tide gauges and satellite altimeters have both depicted similar upward trends in sea level, supporting the hypothesis that sea level is rising at an accelerating rate
Skeptics are able to cherry-pick shorter time periods to cast doubt on sea level rise due to yearly fluctuations in sea level, but looking at the totality of data shows a clear picture
Inaccurate Fact #5: It’s not urgent
Fact: A large amount of warming is delayed, and if we don’t act now we could pass tipping points.
Some people acknowledge the reality of climate change, yet argue that there are far more pressing priorities that policymakers need to act upon now
The urgency of climate change is not immediately obvious as many of its consequences are delayed and currently intangible
However, a quick look at the IPCC’s climate projections clearly shows that the window to mitigate irreversible change is closing, and acting now in the interest of the future is a priority that cannot continue to be shunned
Inaccurate Fact #6: Less than half of published scientists endorse global warming
Fact: Around 97% of climate experts agree that humans are causing global warming.
Numerous studies in peer-reviewed scientific journals show that at least 97% of actively publishing climate scientists agree that climate-warming trends over the past century are extremely likely due to human activities