Navigating Climate Change for Lay People

I'm not a scientist.  My credentials consist of a couple of entry-level university courses, reading of popular science literature such as Scientific American and deep curiosity and concern for the world.  Still, I'm not naturally inclined to believe or do something just because the experts told me so.  I try to balance a healthy skepticism with respect due to scientists who've devoted their careers to inquiry in specialized fields.

So, the topic of climate change has produced a serious quandary for me.  It covers such a huge area of topics that I found it almost impossible for me a as a lay person to completely understand.  Although the bulk of the scientific community has largely rallied behind the science, there is an active community of detractors anchored by a small number of contrarian scientists.  How many are genuine and how many are part of a funded proponents of the fossil fuel industry is a matter of speculation and debate.

The broad strokes of climate change science are simple enough.  The earth's climate is produced by an interaction of heat with the atmosphere, water, and land.  There is a balance between the energy received from the sun's rays and energy radiated off into space. An important part of that balance is the presence of greenhouse gases in the atmosphere such as water vapor, methane (CH4) and carbon dioxide (CO2).  Greenhouse gases absorb a portion of the spectrum of the sun's rays that would otherwise be radiated out into space and radiate the energy back to the earth in the form of infrared radiation.  Without the greenhouse effect, the earth would be too cold to support life as we know it. 

Since the beginning of the industrial revolution, human activity has significantly increased the amounts of 2 greenhouse gases in particular - CO2, which is produced by burning oil, coal and other fuels; and CH4, which is the main component of natural gas. Here's where the complexity comes in.  Although the effect on an annual basis of the additional CO2 and CH4 is slight, it's cumulative over time.  Scientists say that models and experience show that the increased energy over decades and centuries produces significant rises in temperature, affecting the  the biosphere and causing disruption to the conditions that support life which has adapted itself to specific circumstances.  Detractors argue a multitude of contradicting points of view including

1. The world isn't actually warming - perceived warming is due to measurement errors
2. The world is warming but it's not due to human activity
3. The warming exists but it's actually a net benefit
4. The warming exists but it's cheaper to live with it than avoid it

To make it even more complicated, there are numerous types of feedback, both positive and negative, that will affect the ultimate impact that the increased greenhouse gases have.  There are factors like the loss of the albedo effect (cooling due to reflection of energy from pale surfaces like ice) when ice melts, the increase in plant growth due to increased CO2 and the increase in methane when the permafrost melts, and the potential for massive loss of rain forest due to temperature change.

Unless you're a scientist with a significant amount of time invested in this, the chances of you drawing an informed opinion from the details are remote.  So, how do you move forward?  How do you make a decision when the evidence is so complicated, you aren't qualified to evaluate it?

 I've taken a 3-pronged approach to evaluating the problem of whether we should be actively reducing our GHG output:

1. Which side has the most credibility?
2. Which side presents arguments that are most consistent with observed results?
3. What are the relative risks and rewards of of each side?

Credibility
On one side of the debate you have the vast majority of the world's scientific community (no major scientific body disputes the science of climate change), most of the world's governments, and environmental groups.  On the other, you have a small number of contrarian scientists, the fossil fuel industry, right wing politicians and think tanks.  Each side has accused the other of distorting the issue to protect their respective financial interests.  There are persistent claims of industry-funded "astroturf" groups on one side and environmentalists being funded by liberal billionaires on the other.  To me it's difficult to equate the two.  The financial interest of the fossil fuel industry is clearly massively greater than that of climate scientists vying for grants.  If there were something improper about the way climate scientists arrived at their conclusions, the fossil fuel industry with its almost unlimited funds would surely have uncovered it.

Some claim that because the community of climate scientists is relatively small and they peer-review each other's work that group think and confirmation bias have tainted the results.  This is possible - it wouldn't be the first time that the scientific community have gone off in a false direction and shouted down contrarian views.

In my view, the scientific community has significantly greater credibility than the the fossil fuel industry and the few contrarian scientists.  The scientific community is fairly conservative and shies away from the most extreme (and speculative) scenarios that could come from climate change.  Whatever the financial rewards for scientists who publish on the risks of climate change, they pale in comparison to the trillions of dollars of revenue at stake for the fossil fuel industry if carbon intensive industries are curtailed.

Observed Results
To me, this isn't even close.  This chart clearly shows an upward trend in temperature.  All of the 20 hottest years on record have occurred since 1997.  1998 was an unusually hot year due to a a particularly strong el nino and it took several years afterwards for the warming to catch up.  There are still people who are falsely claiming that "warming stopped after 1998".  Other visible signs of warming include the loss of ice in the arctic, glacier loss and the accelerated melt in Greenland and parts of Antarctica.

Some will claim that the warming is due to some other reason besides GHGs (eg sunspots).  They've yet to provide convincing evidence to back that up.

Risk Analysis
It's impossible to be 100% certain of what will happen in the future.  Risk analysis is the practice of considering and adjusting for the effects of uncertainty on outcomes.  There are unlimited possibilities but for the purpose of this exercise, I'll consider 4 scenarios:

1. Climate science has correctly or conservatively determined the causes and effects of climate change; and we continue to increase GHGs
2. Climate science has correctly or conservatively determined the causes and effects of climate change; and we cut GHG's, trending to zero over 25 years.
3. Climate science is wrong about the causes of climate change or has dramatically overestimated the effects; and we continue to increase GHGs
4. Climate science is wrong about the causes of climate change or has dramatically overestimated the effects; and we cut GHGs, trending to zero over 25 years.

Scenario 1 is the disaster envisioned by many climate scientists and environmentalists.  The only benefit I can see is a delay in transition costs to cleaner energy.  The downsides are potentially vast: drought, mass starvation, mass human migration, ocean acidification, greater regions of hurricanes, areas of the world abandoned due to extreme heat and sea level rise. At the same time, fossil fuels will gradually grow scarcer and more expensive. If human migration, food shortages, and water scarcity become extreme, conflict and wars and virtually certain to follow.  Some areas in Canada, Russia and other northern countries may have somewhat enlarged agricultural zones but they will be more than offset by losses in other areas.  Many people seem to focus on extreme weather when contemplating the effects of climate change but I see that as just the tip of the iceberg.

Scenario 2 is scenario 1 but with greater costs due to transitioning energy and much less severe impacts. There are side effects to electrifying the energy system - cleaner air, water and soil.   A few years ago, it was common for people to claim that switching to renewable energy was akin to reverting to the stone age.  Now, however, solar and wind energy are the cheapest forms of new energy and electric vehicles are the fast growing sector of the auto market. Mark Jacobson, Professor of Engineering at Stanford University, has developed scenarios that show 100% renewable energy is not only feasible, but cheaper than continuing to develop fossil fuels.

In scenario 3, global warming either mysteriously abates or it turns out to have more positives than negatives.  It's very unlikely that a warming planet will have a net positive impact to the biosphere in the short term because plants and animals have spent thousands of years adapting to the climate they are in.  A drastic change over a short time frame is normally associated with extinction events.  Although, this scenario avoids the transition cost to cleaner energy, there are still downsides: continued increases in pollution, scarcity & cost of fossil fuels.

Scenario 4 is what fossil fuel companies and climate change deniers fear the most - we'll transition away from fossil fuels and it will be all for nothing.  Will it really, though?  The development and usage of fossil fuels is one of the most environmentally destructive things that people do.  Also, fossil fuels themselves are very unevenly distributed and this distribution has resulted in significant geopolitical strife over the past 100 years.  Even if it costs more in the short term, switching to renewable energy has environmental and geopolitical benefits that can't be measured in dollars.

In summary, I would say that from a risk/reward standpoint, reducing GHG's has greater potential rewards (a cleaner, lower conflict planet) and lesser potential downsides (transition costs vs the potential of societal collapse) than continuing to do what we have been doing.  The risk of continuing to increase GHG emissions is reckless.

Summary
The topic of climate change is incredibly complex, particularly for someone who's not a scientist.  Still, it's possible to logically analyze the options without detailed technical knowledge of the intricacies involved.

To me, it's an easy choice.  When I consider the subject from a standpoint of which side has credibility, which outcome is most aligned to observed results and when I look at potential scenarios, it's clear that the best path is to accelerate the transition to cleaner technologies, eliminate fossil fuels and end the risk practice of using the atmosphere as a dumping ground for GHGs.