Global Warming - Can the average person understand it?

[William_Strunk_Jr]

Is there any way that the average person can understand global warming? Where can the average person go to get the information to understand why global warming has been established in the scientific community to caused by humans and not cycles or changes in the Sun. I don’t think there is any big conspiracy by scientists, but when someone says that Iceland was once a nice warm place to live I don’t know what to say. Is there anyway to understand this issue without years of study? How much time would the average person have to put in to understand this issue?

[Randy_Seltzer]

One of my goals in coming to this board was to gain a further understanding of global warming. I started a GD thread “Fight my ignorance, RE: global warming”. (I’m a guest, so I can’t get to it any more.)

Over the course of the thread, someone (was it Colibri?) made the excellent point that very very few people in the world understand every aspect of our current knowledge of global warming. Even the top climatologists in the world don’t know the ins and outs of every last theory out there. This is one of the major causes of contention in this arena: no one has every answer for the other guy’s arguments.

In light of this, I would suggest you reframe your question. You need to define how well someone needs to understand the issue before you consider it “understood.”

Can the average man understand it well enough to know the basic current scientific consensus? Sure.

Can the average man understand it well enough to take a well-reasoned positin on it? Maybe.

Can the average man understand it well enough to debate it with the average climatologist? No way in hell.

[FRDE]

I think that the problem is that the average person thinks that they can understand it, rather similar to Milton Friedman and Monetarism.

Very simple theories lead to semi-religious followers.

[Seven]

@Randy Seltzer

One of my goals in coming to this board was to gain a further understanding of global warming. I started a GD thread “Fight my ignorance, RE: global warming”. (I’m a guest, so I can’t get to it any more.)

Here

[Kimstu]

@Strunk

I don’t think there is any big conspiracy by scientists, but when someone says that Iceland was once a nice warm place to live I don’t know what to say.

You can point out that historical reports of warmer climates in parts of the northern hemisphere don’t prove the existence of globally higher temperatures in the past. NOAA’s National Climatic Data Center explains:

[T]he evidence for a global (or at least northern hemisphere) “Little Ice Age” from the 15th to 19th centuries as a period when the Earth was generally cooler than in the mid 20th century has more or less stood the test of time as paleoclimatic records have become numerous. The idea of a global or hemispheric “Medieval Warm Period” that was warmer than today however, has turned out to be incorrect. […]

What records that do exist show is that there was no multi-century periods when global or hemispheric temperatures were the same or warmer than in the 20th century. […]

In summary, it appears that the 20th century, and in particular the late 20th century, is likely the warmest the Earth has seen in at least 1200 years.

@Strunk

Is there any way that the average person can understand global warming? Where can the average person go to get the information to understand why global warming has been established in the scientific community to caused by humans and not cycles or changes in the Sun.

As Randy pointed out, there are different levels of understanding involved. The basic premise underlying the current mainstream hypothesis of anthropogenic (human-caused) global warming, or “AGW”, is simple enough to state non-technically in a few sentences:

So-called greenhouse gases such as carbon dioxide in the atmosphere trap radiation from the sun, warming the earth’s surface and the atmosphere. This is the fundamental “greenhouse effect”, which is very important to the development and survival of life as we know it (without such gases in our atmosphere, we’d have much harsher extremes of heat and cold). Over the past couple of centuries, human activities such as fossil-fuel burning and large-scale livestock husbandry have significantly increased the concentrations of greenhouse gases in the atmosphere. And over the past several decades, global temperatures have been rising to an extent and at a rate that has not been satisfactorily explained in terms of normal climate cycles or solar phenomena.

Therefore, scientists have hypothesized that the current warming is mostly or largely caused by an “anthropogenic enhanced greenhouse effect”, due to the increased atmospheric concentrations of greenhouse gases in the atmosphere.

Now, the tough part of the question is: Why is the “enhanced greenhouse effect” or AGW hypothesis generally considered a better explanation of the current temperature increase than other explanations depending on non-anthropogenic factors? That requires a lot more specialized knowledge to understand, and probably nobody who’s not a professional climate scientist understands it fully. But there are lots of summaries for the lay reader available, such as this one:

Theories to Explain Temperature Change

Climatologists accept that the earth has warmed recently. Somewhat more controversial is what may have caused this change. […]

Greenhouse Gas Theory

There are many subtle aspects to the question. Atmospheric scientists know that adding carbon dioxide (CO2) to an atmosphere, with no other changes, will tend to make a planet’s surface warmer. But there is an important amount of water vapor (humidity, clouds) in the Earth’s atmosphere, and water vapor is a strong greenhouse gas. […]

Given this, it is not correct to imagine that there is a debate is between those who “believe in” and “oppose” the theory that adding CO2 to the Earth’s atmosphere will result in warmer surface temperatures on Earth, on average. Rather, the debate is about what the net effect of the addition of CO2 will be, and whether changes in water vapor, clouds, and so on will cancel out its warming effect. […]

Solar Variation Theory

Various hypotheses have been proposed to link terrestrial temperature variations to solar variations. […]

The theories have usually represented one of three types:

1. Solar irradiance changes directly affecting the climate. This is generally considered unlikely, as the variations seem to be small
2. Variations in the ultraviolet component having an effect. The UV component varies by more than the total.
3. Effects mediated by changes in cosmic rays (which are affected by the solar wind, which is affected by the solar output) such as changes in cloud cover. […]

Others

Various other hypotheses have been proposed, including but not limited to:

• The warming is within the range of natural variation and needs no particular explanation
• The warming is a consequence of coming out of a prior cool period — the Little ice age — and needs no other explanation.
• Some skeptics would claim that the warming trend itself is not valid, and therefore does not need any explanation. […]

There’s no way to definitively judge the merits of opposing claims without working through reams of very complicated technical material. The best most of us will be able to do is to understand accurately what the basic issues are, and decide thoughtfully which claims seem most plausible and which sources seem most trustworthy.

[According_to_Pliny]

Al Gore’s movie does a good job. I presume it will play on network TV before long, and probably become a standard for high school science classes.