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The Sheldon Glacier with Mount Barre in the background is seen from Ryder Bay near Rothera Research Station, Adelaide Island, Antarctica.

In facing climate change, what we already know requires a response; it cannot be easily dismissed. Significant levels of scientific consensus—even in a situation with less than full certainty, where the consequences of not acting are serious—justifies, indeed can obligate, our taking action intended to avert potential dangers. In other words, if enough evidence indicates that the present course of action could jeopardize humankind's well-being, prudence dictates taking mitigating or preventative action.

Nearly twelve years ago, the U.S. Catholic bishops emphasized the virtue of prudence in addressing climate change—and this when the scientific consensus around climate change was at a more nascent stage than it is now. Today, as NASA reports, 97% "of climate scientists agree that climate-warming trends over the past century are very likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position." The evidence is now crystal clear, and the only question is: How bad is it going to get?

When the bishops wrote their statement, CO2 concentrations—the primary forcing agent for climate change—was around 365 parts per million (ppm). In a little more than a decade, humankind has increased this to nearly 400 ppm and at current rates, that will reach 450 ppm by mid-century.

Scientists believe that the last time concentrations were this high was during the Pliocene epoch, around 3 million years ago, a time when the Earth’s average temperatures were 5-7 degrees Fahrenheit warmer than they currently are and sea levels were nearly 80 feet higher than they are today. Since that period, scientists believe that naturally changing ocean patterns may have contributed to the significant decrease of atmospheric CO2, and a subsequent decline in global temperatures. Whatever the cause of this CO2 reduction, atmospheric CO2 concentrations stabilized at around 280 parts per million around 10,000 years ago, and lasted until the dawn of the industrial revolution in the 1800s—the time when humanity began releasing unprecedented amounts of greenhouse gases as fossil fuels became the predominant form of energy.

These new CO2 numbers, while not unexpected given the continued reliance on coal, oil, natural gas and other fossil fuels in our economy, are of tremendous concern to climate scientists. Most believe that concentrations must come down to 350 ppm by 2050 in order to avoid runaway and irreversible climate change.

Many hope for some technological fix that will magically appear and suck carbon out of the atmosphere. However, “what we already know requires a response” and that response must begin today in the absence of any such technology on the horizon. That response must include fairly dramatic shifts in lifestyle and consciousness choices—especially on the part of Christians and other people of goodwill. Those choices must include consuming less, living more simply and internalizing a type of solidarity that recognizes that the misery felt by current and future generations facing massive changes in weather patterns is caused by our failure to choose consciously today.

This call to respond is not new. In 1990, Pope John Paul II first brought climate change to the attention of Catholics when he recognized in his 1990 World Day of Peace Message, “The gradual depletion of the ozone layer and the related ‘greenhouse effect’ has now reached crisis proportions.”

Similarly, Pope Benedict XVI, several national Catholic bishops’ conferences, numerous Catholic NGOs and Catholic scholars, and the Catholic Coalition on Climate Change have called for faithful climate action and linking these actions to the wonderful tradition of Catholic social teaching including the Catholic commitments to protect and defend human life and dignity and care for God’s good gift of Creation as well as recognizing that those who have contributed the least to climate change are now and will continue to face its worst consequences: the poor and vulnerable.

In 2006, the USCCB helped formed the Catholic Coalition on Climate Change and charged the membership organization to educate and organize the U.S. Catholic community to respond faithfully to climate change. Key to that effort has been The St. Francis Pledge to Care for Creation and the Poor, encouraging individuals, families, parishes, schools and other organizations to:

PRAY and reflect on the duty to care for God’s Creation and protect the poor and vulnerable.

LEARN about and educate others on the causes and moral dimensions of climate change.

ASSESS how we-as individuals and in our families, parishes and other affiliations-contribute to climate change by our own energy use, consumption, waste, etc.

ACT to change our choices and behaviors to reduce the ways we contribute to climate change.

ADVOCATE for Catholic principles and priorities in climate change discussions and decisions, especially as they impact those who are poor and vulnerable.

Additional online resources can be found on the Coalition’s website and through their Facebook and Twitter @CatholicClimate accounts.

In his Letter to the Ecumenical Patriarch of Constantinople on the Occasion of the Seventh Symposium of the Religion, Science, and the Environment Movement, Pope Benedict XVI declared, “Preservation of the environment, promotion of sustainable development and particular attention to climate change are matters of grave concern for the entire human family.” Now that the atmospheric concentration of CO2 is on the verge of surpassing 400 ppm, humanity has a rapidly-closing window of opportunity to prevent runaway and irreversible climate change. Committing to consistent and conscious individual actions and devoting our vast institutional resources to this problem can be delayed no longer. We must act and we must do so not because it is trendy but because our faith demands it.

Daniel J. Misleh is Executive Director of the Catholic Coalition on Climate Change. Daniel R. DiLeo is Project Manager of the Catholic Coalition on Climate Change and a Ph.D. student in Theological Ethics at Boston College

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ed gleason
9 years 7 months ago
I wonder how conservative Catholics will handle the popular conservative GOP agenda that climate change is a fraud?
JR Cosgrove
9 years 7 months ago
Notice that global warming is gone. This OP only mentioned the term "warm" twice. Maybe because some new thinking believes that CO2 is not responsible. Here is why: http://phys.org/news/2013-05-global-chlorofluorocarbons-carbon-dioxide.html This theory may not be conclusive either but we should understand just how complex climate is and that what we do to supposedly help may in fact have some very undesirable consequences. For some recent articles on global warming for those who still care (I realize this OP is about climate change but for those of you who are confused and think warming is a problem and wonder why it is not mentioned) http://www.forbes.com/sites/peterferrara/2013/05/26/to-the-horror-of-global-warming-alarmists-global-cooling-is-here/ http://www.drroyspencer.com/2013/06/epic-fail-73-climate-models-vs-observations-for-tropical-tropospheric-temperature/ http://www.nytimes.com/2013/06/11/science/earth/what-to-make-of-a-climate-change-plateau.html?_r=2& The question is, are we headed for global cooling and is that the climate change the authors are talking about?
Vincent Gaitley
9 years 7 months ago
Regarding climate change: When I was a young Catholic schoolboy I was taught to carry an umbrella in the rain, to wear a coat in the cold, and to wear boots and gloves as necessary. The rest is panic.
David Rusch
9 years 7 months ago
The 'consensus' is falling apart as the models are significantly (more than 2 standard deviations) above the measurements wrt temperature trends. That is not to say that we should not respect our God given Earth, but it is to say that forced government action is ill advised especially those actions that impact the economy already in serious trouble.
Stanley Kopacz
9 years 7 months ago
Does anyone here really expect that the global temperature rise would be a perfectly linear, monotonically increasing line? Energy is always sloshing back and forth between the ocean and the atmosphere. Similar "pauses" in global warming have been observed before and then they ended, sometimes with a sharp spike upward. In addition, climate models, when run on a computer, display these same behaviours. It is only wishful thinking to think that a powerful greenhouse gas will suddenly have no significance or has stopped working. THis pause will probably end, to be followed by another one after some time in the future, which will then again be naively construed as evidence that global warming is ended. THe CFC theory of Dr. Lu is another false "hope". Photolysis of CFC's in the upper atmosphere is mostly caused by ultraviolet photons from the sun. Dr. Lu's projection of an expanded hole in the ozone layer in 2008/2009 due to reduced solar activity and higher cosmic ray flux did not occur. The bottom line is, no matter what other influences there are, CO2 does what CO2 does independently of the others. If you wear a blanket in the middle of a heat wave, it is illogical to say you are as hot as you are only because it's summer. More CO2 is another blanket. If we are getting a temporary reprieve, we should accept it as such and use the extra time to move toward sustainable energy and conservation. THe automobile is the biggest waster of energy. THe internal combustion engine is about 20% efficient in most cases. Even my Prius Atkinson-cycle engine is only 30% efficient, at most. One more thing, the present global tmperatures are still within the RANGE of predictions of the climate models. IF there is a large deviation, it is only wrt the more "pessimistic" models. Still, these more "Pessimistic" models may prove to be more accurate as the time series progresses.
Richard Savage
9 years 7 months ago
As a meteorologist (Ph.D.), I'm disgusted by Mr. Misleh and his naive accomplice, who obviously know nothing about science - but they know they have a good gig in convincing Catholics to continue funding the CCCC. Meantime, millions of African children die each year of pulmonary disease because their mothers cook over indoor fires of wood and dung. What a wonderful improvement cheap (coal-powered) electricity would make in their lives. How many degrees of "global warming" justify the death of a child? Science is defined by the use of the Scientific Method (SM), described by Francis Bacon and Rene Descartes four hundred years ago. One of the principles of the SM is to consider ALL hypotheses to explain a phenomenon and to attempt to DISPROVE them, by observation and experiment. Instead, the UN's team of "scientists" has a single hypothesis, which they've been trying for 20+ years to prove true. The experiment has settled the matter - the 10% increase in CO2 over the last 15 years has resulted in NO WARMING. As a matter of radiative physics (my dissertation area), this is perfectly understandable. The effect of additional greenhouse gas - CO2 or anything else - is logarithmic. The first fifty (50) parts per million has the most effect; the last fifty - the amount added since 1988's infamous Senate Hearings starring James Hansen - has an unmeasureable effect. It's the Law of Diminishing returns, applied to a greenhouse gas (CO2) that absorbs and emits in a tiny part (5%) of Earth's emission spectrum. Continued emission of CO2 will have the same effect - ZERO. Mr. Misleh's desperation is demonstrated by his assertion that "97% of people who make their living proving CO2 is bad"should convince us. Valid science isn't based on statements of authority, and this one isn't even true; the number was cooked up by a couple of social scientists, based on an email poll. Wake up, fellow Catholics. China and India have plenty of poor people, and plenty of scientifically trained scholars who understand the "global warming" nonsense is a fraud. Those countries are building hundreds of coal-fired electricity generating plants. Think they'd do that if they believed the outrageous lies of the warmists? Richard C. Savage
Stanley Kopacz
9 years 7 months ago
I find your assertions more bullying than convincing. Of course, band saturation reduces the effectiveness of CO2 increase, thank God. Nevertheless, with Doppler broadening and collision broadening, increase in CO2 still results in increased absorption/reradiation. A doubling of CO2 from 10 ppm to 20 ppm is the same as doubling from 270 ppm to 540, and heading toward the latter doubling we are. I have the most trouble with your assertion that the increase in CO2 over the last fifteen years should be matched perfectly by an increase in global surface temperature. Perhaps in a purely atmospheric/land system such as Mars, but not in a dynamic ocean/land/atmosphere system like earth. It can be expected that noise will be superimposed on any ramp in global temperature. You don't have to build centralized electrical systems to help poor people in poor countries. They can be markedly helped by improving the efficiency of their stoves with smart low tech and decentralized power sources such as solar, wind and hydroelectric. Like the logarithmic dependency on CO2, a little electricity versus none will have a lot more incremental benefit than being drowned in it. Depending on coal also guarantees dependence of the poor countries on the coal-rich countries, which works out well for certain economic interests. Unfortunately, the main problem in all countries is that our population and attendant needs are outmatching the support capability of the environment.
Richard Savage
9 years 7 months ago
Amusing, after many years of being called a "climate denier" (echo of "Holocaust denier")by the likes of Al Gore and Obama's OFA, that Mr. Kopacz accuses ME of being a bully. Poor Mr. Misleh. All he has on his side is the US Conference of Catholic Bishops (who pay his salary), the CCCC organization, the Pope, and a vast propaganda apparatus in the media. Wish I could be bullied like that. Mr. Kopacz says nothing about the fraudulent approach by the UN's "climate scientists", who don't use the Scientific Method. That's understandable; his and their ONLY argument is the argument from authority. That doesn't work in Science; as the Nobel winner Richard Feynman said, "No matter how smart you are, no matter how beautiful your theory is, if it doesn't agree with experiment, IT'S WRONG!" Mr. Kopacz goes on to (untruthfully) say: " I have the most trouble with your assertion that the increase in CO2 over the last fifteen years should be matched perfectly by an increase in global surface temperature." No, Mr. Kopacz, I didn't say that, or anything like that. You raised that claim (a strawman) in your previous post. For anyone not familiar with real global temperature measurements, you can see them at http://www.drroyspencer.com/latest-global-temperatures/ Sometimes they zoom up to - gasp! - 0.7 C above the long term mean; sometimes they drop to a few tenths of a degree C below the mean - as a result of a volcanic eruption, or just for no reason we understand at all. For example, in 2007 into early 2008, the global temperature - based on literally millions of satellite measurements - plunged from 0.4 above the mean to 0.25 below the mean. No volcanic eruption was identified as the cause. Like the recent 15 year "plateau" in global warming, the climate models don't explain it. Climate models don't explain or predict El Nino, La Nina, the Indian Monsoon, the African Monsoon, the American Monsoon, the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO), or the Arctic Oscillation (AO). Before repeating his untruth about what climate models have been predicting, perhaps Mr. Kopacz and anyone gullible enough to believe him should look at the graph of their predictions, compared to observations (from weather balloons and satellites) at http://www.drroyspencer.com/2013/06/still-epic-fail-73-climate-models-vs-measurements-running-5-year-means/ Anyone - perhaps excepting Mr. Kopacz - can see the discrepancy between models and observations. As Feynman said, "...if it doesn't agree with experiment, it's wrong." The experiment is continuing. Meanwhile, children are starving and dying, so that we can save them from "climate change."
Stanley Kopacz
9 years 7 months ago
Accidental double post.
Stanley Kopacz
9 years 7 months ago
You say not to accept arguments from authority so I'll ignore your credemtials as a meteorologist. Especially when you said an increase in the CO2 level will result in ZERO change in radiation balance. I simply find this absolutist statement exaggerated and unbelievable for the reasons I mentioned below. Also, all models have limits in temporal and spatial prediction. No meteorological model can tell me what the temperature and humidity will be in my back yard at 1013 on July 5, 2014. Why shouldn't climatic models have proportional limits in resolution. Bottom line, I'm just a guy trying to understand the science better, and ready to accept the fact that science sometimes delivers inconvenient news. Thanks for the link to Spencer. I'll read him and the criticisms. Your emotionalism (words like "hoax") and calling me a liar are further evidence you are less interested in enlightenment than defeating. I don't really care what you think about me. I'm irrelevant. My carbon footprint will go to zero sometimes over the next thirty years, after which, the choices made in my life as an individual and as part of a society may or may not impact future generations. In the meantime, straighten out the AIP with their website http://www.aip.org/history/climate/co2.htm
Richard Savage
9 years 7 months ago
The Scientific Method advises us NOT to accept a theory ONLY on the basis of authority; it must be demonstrable in experimental results. My authority for doubting manmade global warming is based on the result of an experiment underway now for 15+ years: no warming has occurred. Feel free to ignore me, but don't ignore the facts and still claim to be presenting a rational argument. Nor did I call you a liar; I said your statement was untrue - as it was. I didn't write what you claimed; I have no wish to insult you, but I can't let an untrue statement - even if accidental - pass uncorrected. I'm not trying to offend you personally; I merely wish not to be misquoted. Let me explain radiative transfer to you, and anyone else who cares. The Earth, warmed by sunlight, emits infrared (IR) photons upward. A very small number of those photons are of the right wavelength/frequency to excite CO2 molecules in the atmosphere - about 5% of Earth's emission spectrum. An excited molecule very quickly emits that energy and returns to its ground state - its lowest energy state. The emitted energy - new photons - leaves the molecule in ALL directions, i.e., isotropically, half upward (toward cold space) and half downward, back to Earth. That return radiation is what makes the greenhouse effect, mostly from water vapor (H2O), but also from CO2. When the atmosphere contains enough CO2 that ALL the photons at the resonant frequency of the single CO2 absorption line (14.78 microns) in the thermal IR spectrum are being absorbed and emitted, we're reached steady state. There aren't any more IR photons to go around; adding more CO2 has no effect. The greenhouse effect - i.e., warming - is maxed out at that point. It's like adding more insulation in the roof of your house, or putting another blanket on the bed - each increment of insulation, or each additional blanket, has less effect. I'm merely telling you the roof is FULL of insulation; ALL the blankets are on the bed. All the emitted IR that is absorbable/emittable by CO2 is being absorbed and emitted. We're presently at 400 parts per million (even Misleh knows that). By my calculations, adding more CO2 might squeeze another 0.1 or 0.2 degrees C out of the greenhouse effect, but that's in the noise level. Ocean heat release, cloud cover variation, solar variations (we're heading down the sunspot cycle) are all much bigger. One more comment before I quit this conversation: Obama’s speech today will come the day before he leaves for a weeklong trip to three African nations. The First Green President will be flying in hundreds of Secret Service agents and 56 support vehicles including 14 limousines and three trucks. Fighter jets will fly in shifts giving 24-hour coverage over the president’s airspace. This liar - Catholics above all ought to understand that about him - says he's going to convert more food into ethanol and increase energy costs "for the sake of our children." You really think he believes "carbon pollution" is a crisis? Richard

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