http://warisacrime.org/2017/06/28/global-warming-in-a-nutshell/

Last week the 29th anniversary of James Hansen’s historic appearance before the U.S. Senate’s Committee on Health & Natural Resources passed by virtually unnoticed.  Hansen, a climate scientist with NASA’s Goddard Institute of Space Studies, testified back on June 23, 1988, that “Global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and observed warming.”

Hansen added, ”It is already happening now.’’

The year of Hansen’s testimony—1988—was warmer at the time than any other year in the global temperature records, which began in 1880.  Now, it doesn’t even make the top ten.  So far our new century has seen 16 of the top 17 warmest years ever recorded, with each of the last three years setting a new all-time record.  That is not a natural progression.

For 29 years now we have been officially on notice that global warming is taking place and poses serious threats to life as we know it.  And for 29 years, as global temperatures have climbed, we have been unable to muster a serious response.

The core science linking the greenhouse effect and global warming can be summed up in three logical steps:
1)  Carbon dioxide (CO₂) and other greenhouse gases trap heat by absorbing infrared radiation.
2)  The amount of carbon dioxide in the atmosphere is steadily increasing, so more and more heat is being trapped, thus warming the planet.
3)  Human production of carbon dioxide is almost entirely responsible for the increased carbon dioxide levels, and hence for much of the warming.

All three of these steps are easily verifiable. They are based on settled physics and indisputable measurements.

When air sampling began at the remote Pacific island of Mauna Loa, back in 1958, carbon dioxide in the atmosphere was at a level of 280 parts per million (ppm).  This year the CO₂ level reached 410 ppm.  That is a 48% increase of heat-trapping CO₂ in less than 60 years, and the level is still climbing.  Look no further for a reason the world is heating up.

An instrument called a mass spectrometer is used to measure the CO₂ and other gases in the air samples from Mauna Loa and other centers around the globe.  Since CO₂ emitted by the burning of fossil fuels lacks a carbon isotope called C14, the mass spectrometer can tell us how much of the CO₂ being added to the atmosphere came from human burning of fossil fuels.  The answer is: virtually all of it.

Claims that we don’t know whether human use of fossil fuels is responsible for global warming are false.  The science demonstrating that they are false has been known for years.  As James Powell has written, “Unlike people, isotopes do not lie.”

Most people now understand that we need to transition away from CO₂-producing fossil fuels and adopt clean, renewable forms of energy that don’t load the atmosphere with more greenhouse gases.  What they may not be aware of is how quickly we need to cut greenhouse gases, and how deep those cuts must be.

Here’s the problem.  The ocean, plants on land, and other carbon absorbers can only take up about half of the CO₂ humans are currently producing each year.  The other half goes into the atmosphere, where different portions last for differing amounts of time.  The brutal, seldom-discussed reality is that twenty percent or more of the CO₂ humans produce annually will remain in the atmosphere for tens of thousands of years.  That 20% annual addition, on a human scale, is close to permanent.

So to stabilize CO₂ levels in the atmosphere, most of the goals and timelines being set by governments at all levels don’t come close to doing the job.  Even ambitious-sounding goals actually result in dumping more and more gas into the atmosphere, where a good deal of it will remain long term.

The numbers are simple and straightforward.  If we cut CO₂ emissions by 20%?  Then 30% will still go into the atmosphere, CO₂ levels will keep on climbing, and more long-term warming will be locked in.  Cut emissions by 40%?  Then 10% will still worsen the problem.  Every year we don’t cut emissions to 50% of current levels, we’re making things worse.  Much worse.

In short, the minimum realistic goal is to cut CO₂ emissions by 50%, and the realistic timeline is as soon as humanly possible.  Then we can taper down toward zero emissions.  We can’t afford to settle for cuts that are easily palatable.  Our realism should be rooted in physical reality, the real-life consequences of continued greenhouse buildup. The deadly heat waves, drying out of soils, increased flooding, more violent storms, mass migrations of plant and animal species, melting of ice caps and glaciers, and all the rest of it.

What we think of as “other issues” keep pressing themselves on us.  Health care.  Terrorism.  Poverty.  Immigration.  Hunger.

The fact is, global warming will worsen every one of these dramatically, on a planetary scale, and will do irreparable harm in many other ways.  Global warming is the biggest, most comprehensive threat the world faces.  Dealing with it must become the number one priority on our political agenda.