Editor's note: This is part of GlobalSpec's Point/Counterpoint series of articles, which seeks to foster constructive discussion around divisive topics in technology and science. Read this article's companion piece, Counterpoint: The data is clear - climate change is real and happening.

Climate change is a dominant political, social and environmental force in the 21st century. Climate change proponents believe that the world's atmosphere has increasing variability and volatility. In their view, the aggregate result is a climate that is increasingly warm, and potentially dangerous from resultant sea level rise, droughts and storms. And the cause is additional atmospheric carbon dioxide from human behaviors.

Some estimates state that 97% climate scientists agree on the above facts. However, the remaining 3% is a boisterous minority, that cite some of the following evidence as reasons for disbelief. Some believe in a "global cooling," others believe the risks are exaggerated, and another cohort believes humans are not the cause.

These are positions that have drawn a few notable scientific minds. One of those being Roy G. Spencer, award-winning meteorologist and researcher at University of Alabama - Huntsville. In his 2018 book, "Global Warming Skepticism for Busy People," he wrote, "Catastrophic climate change is a matter of faith—not science. Another way to phrase it is, the scientific support for a small portion of predicted warming is pretty good, while for strong warming it is extremely speculative."

Here is some of the leading evidence against climate change.

Figure 1. Sea level models vs. observations. Source: IPCCFigure 1. Sea level models vs. observations. Source: IPCCClimate change models are not enough

Scientists use climate change models to understand global weather trends. Climate models are mathematical equations based on environmental research used to describe the interactions between the physical, chemical and biological properties in the atmosphere, ocean, land, sea and polar regions. In terms of climate change, they are used for analyzing how the global climate will react to increasing greenhouse gas concentrations.

Many climate change deniers take issue with such models, and cite records errors. The errors can be due to human mistakes encountered when gathering, storing or interpreting data gotten from the earth’s physical, chemical and biological resources.

It is not unusual for climate change projections to vary widely across climate models, and this invokes questions about their reliability. Figure 1 shows global sea-level rise projections from 1990-2010 of two different climate models. Both projections were produced from climate models obtained from tide gauges and satellite observations, indicated in red and blue bands respectively. The two climate models’ projections of global sea level rise were erroneous and differed from reality – the IPCC climate models represented in gray bands.

Temperature record

Climate change predictions rely heavily on temperature data. This data is recorded from approximately 30,000 weather stations spread out throughout the world.

Climate change opponents often cite this data as unreliable, and indeed some studies have found errors with weather station location. Too often stations instruments are located for convenience – say in the asphalt parking lot of a university's science department – than being located for data integrity.

In a study conducted at the National Climatic Data Center on temperature data gotten from weather stations in poor locations around the world found that weather stations that are "poorly sited actually showed slightly cooler maximum daily temperatures compared to the average.”

Considering that gradual temperature change is a key tenet of climate change, this is an easy way to discredit climate change data.

Effects of increased CO2

Figure 2. Uncertainty in climate sensitivity. Source: Roe and Baker ScienceFigure 2. Uncertainty in climate sensitivity. Source: Roe and Baker Science

It was observed in the IPCC fourth assessment report that doubling the Earth's CO2 would increase the planet’s temperature by a small margin, likely in the range of 2 to 4.5° C, with a best estimate of 3°.

This is counter to some climate change theories that posit higher estimates in similar time frames. First, a doubling of atmospheric CO2 is a generous assumption for the amount of CO2 produced. And this also indicates that climate change may be happening at a slower pace than some studies suggest, meaning that there is more time for further, potentially more accurate, investigations and action plans.

CO2 comes from warmer temperature

Figure 3. Carbon dioxide and temperature temporal trends. Source: Vostok Antarctic ice core records for carbon dioxide concentration (Petit 2000) and temperature change (Barnola 2003).Figure 3. Carbon dioxide and temperature temporal trends. Source: Vostok Antarctic ice core records for carbon dioxide concentration (Petit 2000) and temperature change (Barnola 2003).s

Thanks to Antarctic ice cores, researchers are able to study the relationships between atmospheric CO2 and temperature for the last 400,000 years of Earth's history. This research has largely concluded that CO2 levels is not the primary contributor to climatic temperature rise.

Some data suggests that initial temperature rise occurred before CO2 increases, which was fueled by the Earth's natural celestial mechanics. As oceans rose, they released additional CO2, which continues in phases today. Atmospheric CO2 is both a cause and effect of climate change, and humans in this case are not the drivers of climate change, but rather a passenger.

Conclusion

Among the scientific community, climate change is practically a given. However, there is ample room for improvement in climate change research, as it has become error prone. It is research that thousands or millions are working on, and the high variability of the predictions and data quality lead to questions in the theory's overall validity.