Before Al Gore

[Keepitsimple]

I came across this NASA article on Global Warming (from 1998) and found it's contents to be refreshingly balanced and not caught up in the generalities and polarization that hinder discussions today. A few short years later the "science was settled" but in fact, many of the same issues and uncertainties still exist. I couldn't help but notice the lack of "alarmism" and seeming geniune quest for steady, measured scientific knowledge.

Getting reliable predictions from models is difficult

because many of the secondary processes are not

understood. For example, when temperatures start to

warm because of the direct radiative effect of increasing

carbon dioxide, will clouds increase or decrease? Will

they let in less radiation from the sun, or more? These

secondary processes are important.

The direct radiative effect of doubling carbon dioxide is

relatively small, and there is not much disagreement on

this point among models. Where models conflict is in

regard to the secondary, or feedback effects. Models

that predict a very large warming from carbon dioxide

show cloud cover changes that greatly amplify the

warming effects, while models that predict moremodest

warming show that clouds have a small or even

damping effect on the warming.

Can we match the observation of temperature trends

with the model predictions? The temperature record of

the past hundred years does show a warming trend, by

approximately 0.5°C. However, the observed warming

trend is not entirely consistent with the carbon dioxide

change. Most of the temperature increase occurred

before 1940, after which Earth started to cool until the

early seventies, when warming resumed. Carbon

dioxide, on the other hand, has been increasing steadily

throughout the past century. Other factors that could

have affected climate during this period include the

possible change in the solar energy reaching Earth, the

cooling effects of volcanic aerosols, and the possibility

that sulfur dioxide and other pollutants might be

affecting the amount of solar radiation that is reflected

back to space. Some of these effects can cause a

cooling that could counteract the warming due to

carbon dioxide and other greenhouse gases. All of

these effects would have to be taken into account and

appropriately modeled in order to predict the changes

that one might expect in the next century.

Link: http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/eos/global_warming.pdf

Edited April 30, 2010 by Keepitsimple

[Michael Hardner]

I came across this NASA article on Global Warming (from 1998) and found it's contents to be refreshingly balanced and not caught up in the generalities and polarization that hinder discussions today. A few short years later the "science was settled" but in fact, maybe of the same issues and uncertainties still exist. I couldn't help but notice the lack of "alarmism" and seeming geniune quest for steady, measured scientific knowledge.

Link: http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/eos/global_warming.pdf

This is the language of science, not the ways of Glenn Beck, Al Gore, or this board.

[Guest TrueMetis]

I came across this NASA article on Global Warming (from 1998) and found it's contents to be refreshingly balanced and not caught up in the generalities and polarization that hinder discussions today. A few short years later the "science was settled" but in fact, maybe of the same issues and uncertainties still exist. I couldn't help but notice the lack of "alarmism" and seeming geniune quest for steady, measured scientific knowledge.

Link: http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/eos/global_warming.pdf

You would get the same thing from any actual scientific paper.

[Bonam]

Yup, that's pretty much how real science summary reports read. Models have come a long way since 1998, however, and while some uncertainties remain, many of the questions and unknowns mentioned in that NASA article have since become better understood.