Climate Denial #2 - False Logic and Conspiracies

Nov 18, 2019

Second in my series of “factoid” posts about climate denial. As I said in the first one, these are not intended for actual climate deniers. These are for people who are “climate-aware” — to provide useful Information that might clarify things in your own mind. As usual many thanks to Alina Goh.

False Logic #1: Climate’s changed before

Reality: Climate reacts to whatever forces it to change at the time; humans are now the dominant forcing.

It is true that climate has changed before - climate is constantly changing in response to various forcings, often over long periods of time
Past changes have been connected to factors such as solar irradiance, Milankovitch cycles or volcanic activity
None of these factors can explain current climate change: solar irradiance has been decreasing for several decades, while Milankovitch cycles would also support a current cooling period
CO2 emissions from volcanic activity are negligible compared to human emissions: the eruption of Mt. Pinatubo in 1991 emitted CO2 equivalent to 0.2% of human emissions in the same year
It is even more clear that humans are the dominant forcing of current climate change through the isotopic argument. Sharp decreases in atmospheric carbon-13 (attributed to volcanic matter) alongside increases in carbon-12 (attributed to organic matter aka fossil fuels) from the Industrial Revolution till now suggest that increased fossil fuel combustion has driven recent concentrations in atmospheric CO2.

False Logic #2: We’re heading into an ice age

Reality: Worry about global warming impacts in the next 100 years, not an ice age in over 10,000 years.

It is true that the Earth has historically experienced regular ice ages in response to Milankovitch cycles, and the timing is right for the next ice age to occur
Despite this, the atmospheric CO2 concentration is far above 300ppm, which generates an infrared warming effect that outweighs the cooling effect of Milankovitch cycles
Sustained high CO2 concentrations mean that any potential cooling effects will be cancelled out by warming effects, so the probability of an ice age occurring anytime soon is negligible

False Logic #3: It’s Urban Heat Island effect

Reality: Urban and rural regions show the same warming trend.

Urban Heat Island effect describes built-up areas that are hotter than nearby rural areas, in part due to heat-absorbent materials that make up many cities
Urban areas can experience a 1-3 degrees celsius difference with surrounding rural areas, leading skeptics to conclude that the phenomenon of global warming is really just a myth felt by urban dwellers
In reality, organisations like NASA GISS have painstakingly removed any possible influence from Urban Heat Island effect in their climate models
When comparing rural and urban warming trends, although rural areas are cooler than urban areas at a given point in time, both areas display near-identical warming trends over time, showing that excess urban warmth has no effect on the long-term warming of the climate

False Logic #4: The Medieval Warm Period was warmer

Reality: Globally averaged temperature is now higher than global temperature in medieval times

The Medieval Warm Period was a period of warm climate from about 900-1300 AD
Data from ice cores, isotope ratios in marine organisms, and other sources point to regional temperatures exceeding the 1961-1990 baseline average temperature
Despite the evidence of warm regions, there were also areas like central Eurasia and northwestern North America that displayed substantially cooler temperatures
When constructed into a global average, the data indicates that the Medieval Warm Period had a cooler average temperature than what exists today

False Logic #5: Human CO2 is a tiny % of CO2 emissions

Reality: The natural cycle adds and removes CO2 to keep a balance; humans add extra CO2 without removing any.

In comparison to the total natural emissions from the carbon cycle, human emissions seem minuscule
The Global Carbon Project estimated that CO2 emissions from fossil fuel energy sources hit a record high of 37.1 billion tons in 2018, although that number pales in comparison to the nearly 800 billion tons of CO2 emitted from vegetation, land and oceans each year
The key difference is that natural emissions are part of a cycle, with commensurate amounts of CO2 being absorbed back into carbon sinks
Human emissions are a one-way street, and natural carbon sinks have a limited capacity to absorb extra amounts of CO2
This disruption of the carbon cycle leaves leftover CO2 in the atmosphere, thus enhancing greenhouse effect and accelerating climate change effects

False Logic #6: CO2 was higher in the past

Reality: When CO2 was higher in the past, the sun was cooler.

It is true that CO2 concentrations have been higher at certain points in history than currently
However, during some of these periods, the planet also experienced glaciation, underlining the key point that CO2 is not the only driver of climate
Another key forcing of climate is heat from the sun, which at these points was a counteractive cooling force to the CO2 concentration in the atmosphere
Warming temperatures today can be attributed to CO2 concentrations from human emissions both by looking at the isotopic makeup of atmospheric CO2 and the decreasing total solar irradiation in the past several decades

Conspiracy #1: Peer review process was corrupted

Reality: An Independent Review concluded that CRU’s actions were normal and didn’t threaten the integrity of peer review.

In 2009, leaked emails from the Climate Research Unit at the University of East Anglia seemed to show corruption in the peer review process of several climate research papers
This “Climategate” scandal cast doubt on the motives and honesty of the researchers, who allegedly hijacked the peer review process to promote a favoured conclusion that possibly aligned with a wider political agenda
Various probes and investigations found that, when put into the wider context of the overall conversation, emails that seemed damning in isolation did not undermine scientists’ rigour and honesty, and did not prejudice advice given to policymakers

Conspiracy #2: IPCC is alarmist

Reality: Numerous papers have documented how IPCC predictions are more likely to underestimate the climate response.

Skeptics posit that the IPCC is politically motivated to build a case for humanity being the primary cause of global warming
When IPCC predictions are compared to observed data, it is clear that the IPCC errs on the side of caution as opposed to exaggerating their predictions
The IPCC has made conservative predictions for greenhouse gas emissions, attribution of global warming to humans, sea level rise and arctic sea ice decline projections