Are You a Climate Skeptic? Keep Reading…

A busy layperson’s (sourced) guide to claims and facts about climate science

Greenland southwestern coastline. Photo credit: NASA

If you are a climate denier that is convinced everything is a hoax, this isn’t for you. And if, conversely, you are all-in on tackling the climate challenge, you can skip this as well. But if you are curious or confused and refining your views, this can help.

Years ago I went down the rabbit hole of research to inform my views. I hadn’t thought to share this before but three recent events made me think my cliff-notes might be useful to others: (1) the Republican primary debate where at least one candidate — vying for a position of untold power on this issue — claimed to an audience of millions that climate change was a hoax, (2) an All-In podcast episode where 3 of 4 *extremely* opinionated individuals on all sorts of subjects in which they are hardly subject matter experts, with the resources and need to develop a point of view on this issue, were unwilling or unable to firmly express a position on climate change; and (3) a new declaration including a couple of Nobel Prize-winning (non-climate) scientists circulated stating there is no climate emergency (the irony of touting that there are over a thousand signatories yet not caring about consensus, but I digress).

So first of all, here is a summary (with lots of links and references in case you want to do your own research which I strongly encourage) of the most common arguments used to deny anthropogenic climate change:

1. Temperatures have always changed and it has been much warmer many times in the past 10,000 years without devastating consequences. While experts concur that Earth has experienced vast fluctuations in temperature in the past, aggregate data shows that the current pace of increase is much faster than after any other ice age. The consequences for humankind in prior periods were also not as dramatic as they would be today given the explosion in world population, current sea levels, and extensive land development supporting our way of life.
2. CO₂ levels have been way higher without devastating consequences. Books such as Inconvenient Facts use lots of graphs (with incomplete data and cherry picked locations/subsets) to suggest that mammals and humans thrived during periods of much higher CO₂ concentrations. However, NASA data shows we have never had CO₂ levels as high as now, and the increase has been highly connected to the industrial revolution.
3. There isn’t consensus in the scientific community. Claims that scientists signed confusing statements or that climate advocates have calculated the percentages misleadingly are often cited to discredit the statistic that 97% of scientists believe climate change is real and increasingly man-made (note 98% believe in evolution). Notwithstanding, endless studies have validated this since. Not surprisingly, the dissenters get disproportionate media airtime making the controversy appear more real.
4. Models overstate the warming effects vs. reality. Articles claim studies that dispute the validity of models are ignored by experts. However, in every case I looked into when one digs into the actual source data they actually reinforce the conclusion of accelerated warming and higher temperatures.
5. Vapor is the most significant greenhouse gas, which is not man-made. Thus focusing on CO₂ is a waste of time. Climate change deniers correctly point out that water vapor is the most abundant greenhouse gas accounting for about half of our planet’s greenhouse effect. However, they mislead by implying that due to this fact, focusing on the sliver of man-made gases is irrational, when experts (as noted by NASA on its site) clarify “some people mistakenly believe water vapor is the main driver of Earth’s current warming. But increased water vapor doesn’t cause global warming. Instead, it’s a consequence of it. Increased water vapor in the atmosphere amplifies the warming caused by other greenhouse gases”
6. Melting glaciers don’t matter since ice melting in water doesn’t cause levels to rise. While it is true that melting ice inside water does not cause water level rise, sea level rise estimates already take this into account. The majority of sea rise will come from melting ice outside of the water, and the additional increment comes from the fact that melting saltwater does create a volume increase, albeit slight. Further controversy is sowed when localized data points are used, even though the peer reviewed analyses acknowledge this but correctly estimate overall global impact.
7. CO₂ is a net positive for humankind. There is no dispute that (a) extreme cold is incredibly harmful for humans, (b) fertilizer increases agricultural productivity, and (c) some regions will benefit from temperatures rising, even if it is a net negative for global population and the planet. However, experts at non-profits such as the CO₂ Coalition would like us to believe that we should cheer for a warming world, rather than be concerned about the dramatic changes to the way of life we have established within the narrow band of variables we have been living with for the last several thousand years. To do so they showcase specific one-off data rather than consider the aggregate net impact of a complex global system of many interrelated variables. For example, while CO₂ stimulates some plant growth, the combination with nitrogen limitations, drought, and higher temperatures resulting from higher CO₂ levels negate this effect.

In summary, you can see the “hoax” claims are generally supported with cherry-picked data, generalizations, or poorly drawn conclusions even if from correct datasets.

But let’s set something straight: we will never have 100% certainty about this issue. Scientific theories, unlike scientific laws, cannot be proven with an equation. Scientists express degrees of confidence about various theories, and “high confidence” means there is very high certainty amongst experts that it is correct.

Obviously, no one can be an expert on everything. Not even the most knowledgeable climate scientists work in a vacuum, as the topic itself is a complex integration of geology, atmospheric sciences, oceanography, etc. Individual experts contribute to the aggregate knowledge base, and through peer review the best knowledge survives and spreads, ensuring data integrity and coherent analysis (as an aside, if you haven’t followed the controversy around room temperature superconductors, please enjoy digging into vicious accusations here and observe the peer review process at work here). For the rest of us (be it a politician, CEO, investor, or any responsible member of society), the only way to develop an informed view is to absorb a broad range of quality information and seek out the best counterpoints to your views, then qualify, refine, and analyze to develop a perspective.

Is it possible the scientific community is wrong? Yes. Likely? No. Given current knowledge and risk assessment, should we steer our economy towards more fossil-fuel burning and thus global warming rather than less? Seems crazy to me.

Based on my analysis, I believe the facts are clear, the interpretation is open to slight debate, and where the real controversy lies is in deciding how much of our collective efforts and capital to devote to a hard problem, with hard to quantify risks, with near-term costs. And I think think those debates are legitimate and we should all be having them.

Should we invest more in adaptation or mitigation? Use carbon pricing or subsidize new technologies? Invest in current or future big markets and economies? How should we trade off current vs. future GDP growth? How about current vs. future well-being? Is it fair to limit the global poor’s access to carbon-emitting fuels before we have equally cheap green alternatives? Do we want to penalize cattle farmers and limit meat and dairy consumption? Should air travel, big homes, fast fashion, and other conveniences of modern society be limited due to their climate impact? Should we prioritize greenhouse gas reduction over other environmental concerns such as ocean plastics, deforestation, and habitat destruction? These are all highly complex, sensitive, and important concerns with no agreed upon consensus or factual “correct” answers. Each of us bring our own perspective and opinions, and we should endeavor to have constructive dialogues to reach compromises and a workable roadmap for global wellbeing.

Personally I’ve concluded humankind should invest meaningfully to mitigate the risk given we have only one livable planet, while investing in a future economy that does not reduce our standards of living. I believe this can be achieved by rebuilding our massive economy sustainably, using the wealth of our fossil-fuel-based economy to fund the transition as quickly as possible. And I recognize others may have different positions which I’m open to considering and learning about.

But after doing all this work, my conclusion is that if these debates do not rest on the acknowledgement that climate change is accelerating and is increasingly man-made, they are not sincere or constructive for the world we all hope for humanity to inhabit for generations to come.

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