­­ CC - Introduction

Conscious Climate: Introduction

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WARNING! This one-page outline of human-caused climate change makes for grim reading. It provides basic evidence underlying a recent and growing realization: that the fossil fuels (coal, oil and natural gas) on which our modern industrial world is built come with a staggering cost. It conveys scientists’ warning that if we don’t begin a massive shift to carbon-free sources of energy very soon, we risk unleashing an avalanche of climate destabilization which we may well be unable to adapt to, let alone control.

NEVERTHELESS, the way forward is clear, if not easy. We can avoid climate catastrophe, but there is a deadline. Learn the basics of climate change (this page) or dig deeper (the rest of this site). Tell others. And let your political leaders know you want real climate-change action (that means a price on carbon) NOW.

Fact 1: CO2 and other greenhouse gases trap heat.


The story of human-induced climate change (comprehensive time-line here) begins with a physics discovery from the 1860s: that CO2 absorbs long-wave radiation (the video to the right provides a lab demo; commercial CO2 sensors are one practical application).

This basic physical property of CO2 (and other greenhouse gases like methane and water vapor) plays out on a planetary scale as the natural greenhouse effect, raising Earth’s mean surface temperature 33C° higher than it would otherwise be, and making life possible.

Modern energy-flow studies show, in fact, that the amount of trapped long-wave radiation (333 W/m²) scattered back to Earth’s surface from the CO2-blanketed atmosphere is over twice the average amount of short-wave radiation (161 W/m²) it receives from the sun!

Again, CO2 does not act alone: water vapor, far more abundant and powerful, contributes roughly 50% to the average greenhouse effect (vs. 19% for CO2). But water vapor concentrations, responding quickly to air and ocean temperatures, function as a feedback, not a driver, of climate; among the gaseous forcings of climate, CO2 remains dominant.


Fact 2: Earth’s atmospheric CO2 blanket is thickening.

  The NOAA animation to the right tracks actual measured¹ atmospheric CO2 concentrations (y-axis, in parts per million) at various latitudes (sine -1.0 = 90° South; sine +1.0 = 90° North) over time. The wavy line drifts upwards as CO2 levels climb year by year (date in upper-right corner), with Northern values rising during winter/spring as plants decay and release CO2, and dropping during summer/fall as growing plants breathe it in (followed six months later in the South, to a lesser degree due to more ocean and fewer land plants).

A NASA animation of Earth “breathing,” using the famous Keeling Curve to track the same trend, shows current atmospheric CO2 levels up about 40% from a stable pre-industrial 280 ppm (and ice-age levels as low as ~180 ppm). Ice-core evidence suggests current levels top anything in the last 800,000 years, and recent isotope studies indicate that the last time atmospheric CO2 levels were this high was 14-20 million years ago, on a planet quite alien to the one on which our species evolved (about 200,000 years ago), learned to farm (8,000 years ago) and built our modern industrial civilization.

The speed with which we are thickening Earth’s greenhouse blanket is critical in determining our and other species’ ability to adapt. That’s a scary thought, given that recent atmospheric CO2 growth rates are about sixty times faster than the steepest increases seen in ice cores, with emissions growth likely to accelerate as countries like India and China industrialize.

¹ Here’s who does the measuring - and where and how.

Animation courtesty of NOAA’s ESRL Global Monitoring Division.

Fact 1 + fact 2 = fact 3: Earth has a fever.

  Evidence for a coupling of atmospheric CO2 levels and global temperatures throughout Earth’s 4.6-billion-year history is compelling. And it’s not just surface temperatures. Our featured video points out that the recent surface temperature record, likely unprecedented in at least the last 1700 years, reflects but a fraction of Earth’s energy imbalance of 0.9 W/m², since most of the excess trapped energy¹ ends up in the ocean.

Even so, climate-change skeptics have vigorously attacked the surface-temperature record, citing data adjustments, siting deficiencies, station drop-out, and recent cooling. These and other accusations have proven unfounded (see adjustments, siting, drop-outs and cooling respectively); surface temperatures and multiple other lines of evidence bear ever-stronger witness that Earth has a fever.

¹How much energy? Though substantial uncertainties remain, current best estimates - based on observations of outgoing and downward long-wave radiation and of ocean heat content - suggest that the extra energy trapped by our thickened greenhouse blanket is equivalent to that released by exploding eight Hiroshima-sized nuclear weapons every second (0.9 W/m² = 0.5 PW total = 500 TJ/second, versus a yield of 63 TJ from the Hiroshima bomb).


Fact 4: Who or what is responsible? We are.

  Could something else be causing Earth to overheat? The IPCC graphic (at right) compares actual surface temperature observations with advanced climate-model simulations. Only when GHG emissions are input along with natural forcings can the models reproduce recent temperature observations. (And we know the culprit emissions are from fossil fuels because the ancient carbon in coal, oil and natural gas has its own isotopic signature.)

There’s more: not only do “basic physics” and a growing series of “fingerprint studies” (based on patterns of climate response unique to different forcing agents) all point to a thickened GHG blanket as the chief cause of recent global warming — other potential suspects all have alibis:

and could not, in any case, alter the “smoking gun” represented by facts 1 and 2, above.

Like court-room lawyers (the distinction between lawyers and scientists is important!), defenders of the fossil-fuel status quo press their case. But so far, their arguments have all failed under cross-examination (may it please the Court: exhibit A, exhibit B and exhibit C).


Fact 5: Current impacts are already serious - and growing.

  Given natural climate variability, scientists are cautious about attributing single events to a global-mean temperature increase of “only” 0.8°C (1.5°F) since 1880, preferring instead to invoke altered probabilities. Meanwhile the “maybes” accumulate, many of them unanticipated and all of them consistent with the known physics of greenhouse warming:

Recent comprehensive reviews of these and similar indicators and impacts - at global, regional and national scales - point to one conclusion: human-induced climate change isn’t coming. It’s here.


Fact 6: “Business as usual” leads to catastrophe.

  Earth’s current GHG blanket requires a further 0.6°C temperature rise before balance is restored, so we’re already committed to impacts beyond those of the 0.8°C warming we’ve seen so far; if (as the fossil-fuel lobby urges) we continue pumping out CO2, an even higher fever will ensue. So when does it become truly dangerous?

M.I.T., the UK’s Met Office and others warn the IPCC’s oft-quoted limit of 2°C above pre-industrial times (now viewed as being riskier than originally thought) will soon be all but unreachable. Our interactive map (right) hints at what we face if they’re right; so do the hour-long video A Really Inconvenient Truth, this Oxford University workshop, these National Geographic shorts from the book Six Degrees, and a growing list of studies like these on future drought and temperature extremes.

After years of growing concern, the US military now includes climate change in its formal security review process, echoing a 2007 German assessment that business-as-usual means “...climate change will draw ever-deeper lines of division and conflict in international relations, triggering numerous conflicts between and within countries over the distribution of resources, especially water and land, over the management of migration, or over compensation payments between the countries mainly responsible for climate change and those countries most affected by its destructive effects.”

UK Met Office Oct '09; click for full-screen version; see also Canadian summary.

Fact 7: The ultimate risk: blindly passing a point of no return.

  We need to address climate change NOW - first, because of powerful natural, technological and political inertias; and second, to avoid triggering overwhelming natural feedbacks.

Natural inertias include the persistence of CO2 in the atmosphere and the heat capacity of the oceans. Technological intertia builds as new investments in coal coal and tar sands projects guarantee decades of future pollution, waste resources and forestall the innovation needed to develop clean alternatives. Political inertia derives not only from entrenched coal, oil and ideological heavyweights, but from the sunk costs (think house mortgages and truck loans) of regular folks whose livelihoods are currently part of the fossil-fuel economy.

That’s bad enough. But what really panics scientists (and some business sectors, including insurers), is the possibility that sustained warming could trigger natural feedbacks that would boost earth’s fever beyond all hope of recovery or accomodation.

The timing of tipping points is uncertain, but scientists already note a feedback response in water-vapor and in methane bubbling up from arctic lakes and parts of the Siberian and West Spitzbergen sea-floors. A 2010 report (PDF here) calculates an albedo feedback from 2010’s melt of Arctic sea-ice, snow and permafrost equivalent to three gigatons of additional CO2 emissions, ie. the output of 500 large coal power plants, and a recent NSIDC study quantifies an equally-frightening release of CO2 and methane from melting permafrost.

Find the full McKibben lecture (82 min., indexed) here.

Fact 8: Sufficient clean-energy technologies are already available.

  We don’t need to keep burning fossil fuels. In fact, fortunes will be made in the shift to a world-wide clean-energy economy. And the opportunities will be many: the sheer magnitude of the challenge will require a “buckshot” approach rather than a single magic bullet.

Take away the hype and the fact remains: alternatives to fossil fuels abound (summary here), with vast opportunities ahead in efficiency, wind, concentrated solar thermal, photo-voltaic, biofuels, geothermal, tidal, nuclear (or not), and transportation.

The prime tasks involve deployment of existing technologies, creation of smart grids to connect clean-energy sources to their markets and, for resources like wind and solar, overcoming problems of intermittency. Even in these early days, there is no lack of local, regional (and here), national and international plans being promoted or implemented.

Critics warn the transition to a low-carbon economy is unaffordable. But even cost-only estimates by the US CBO are surprisingly modest, and more comprehensive analyses foresee massive financial and employment gains in an abundance of “low-hanging fruit” (eg. efficiency opportunities) that can, in fact, improve the business bottom line (something to which a growing list of major companies can attest) — and create competitive advantages for those countries that are first to embrace the clean-energy imperative.

Australia? What about Canada, the US, Europe, China? Click here for more plans!

Fact 9: Needed NOW: new rules of the game.

  The inability of energy markets to incorporate the full cost of fossil-fuels in their prices amounts to what economists call a “market failure,” an illustration of the “tragedy of the commons” and, most important in pracitcal terms, a reminder that free markets need government - to enforce rules, set boundaries and, where necessary, adjust incentives to compensate for economic blind-spots.

Target concentrations aside, climate inertias and potential tipping-points mean that humanity needs to eliminate net GHG emissions and deploy clean-energy technologies with war-time urgency. The market can match a thousand solutions to a thousand challenges, provided governments make appropriate use of their full tool-box:

  • regulations to boost fuel efficiency in transportation, buildings and appliances
  • incentives, where necessary, for the most critical clean-energy technologies and infrastructures
  • the elimination of subsidies for fossil fuels and, most critically,
  • a progressively tougher cap-and-trade system or rising carbon tax to supply the price signals that investors and entrepreneurs require to build the new energy economy.

Political leaders will not hazard such measures without voter support from all parts of the ideological spectrum. Are our democracies up to the challenge? More to the point, are you? Educate yourself, then speak out - to friends, the media and, most important, government!

Visit Yale for more on Global Warming’s Six Americas!