Carbon Neutrality is not enough.

US Believes only way out of global warming is to go carbon negative

Nuclear power plant

US is looking at ways of becoming carbon-negative.

A good start would be to deny the XL Pipeline. However: sequestration has its advocates. To suck up some of the dangerous CO2 levels of the past few decades.

With the mostly failed campaign to prevent climate change from raising global temperatures by more than 2 degrees Celsius, and no real prospect of rolling out significant amounts of renewable power generation in time to prevent a global meltdown, it looks like society only has two real options: Roll out a lot of nuclear power stations right now, or start burying (sequestering) gigatons of carbon dioxide underground. The nuclear option is looking unlikely — but sequestering carbon might just work, if some recent studies are to be believed. A new report from the Risky Business Project has laid out the long-term consequences of continued climate change for various geographical areas of the United States. Rather than focusing on incredibly dense scientific language, the RBP is led by the business community and emphasizes research conducted by economic firms. The goal was to create a report that would discuss the disruptive impact of climate change on businesses and the US economy. The result is an approachable report that discusses likely impacts to the US by splitting the country into multiple regions and estimating the chances of various outcomes. The following graph, for example, shows how the increasing likelihood of extreme weather events impacts observed conditions, even if no single storm, heat wave, or abnormally cold winter can be directly linked to global warming.

ExtremeWeather

With our mostly failed attempt to keep climate change below 2 Celisus, the new critical question is how governments might hold the increase to as low a level as possible. Despite improvements, no one seriously expects renewable energy to be ramped up in time to prevent climate change far in excess of 2C — the only way to avoid this limit would be to convert to nuclear or renewable power at a breakneck pace across the entire planet for the next few decades.It’s not going to happen. So what can we do? It turns out, we might be able to do rather a lot. Whenever the Intergovernmental Panel on Climate Change (IPCC) issues its reports, a great deal of energy gets expended arguing about the reality of climate change. Some of the IPCC’s  more interesting ideas go undiscussed as a result, including the long-term potential for CCS — carbon capture and storage. According to the IPCC, CCS systems are absolutely vital to minimizing the long-term impact of greenhouse gas emissions. [Read: Nuclear power is our only hope, or, the greatest environmentalist hypocrisy of all time.]

Going carbon negative

Many companies today tout various technologies they claim allow them to be carbon neutral, but the only way to hold climate change below 2C in the long term is to actually go carbon negative. This can be achieved through the use of bio-energy with carbon capture and storage, or BECCS for short. The idea is straightforward — as of last year, approximately 10% of total planetary energy was provided by biomass. Plants absorb CO2 as they grow, but the process of turning biomass into fuel typically releases that energy back into the atmosphere. What the IPCC proposes is using the biomass for energy, then using some of the energy generated to sequester the carbon underground in either old oil and gas deposits or in porous rock (known as saline formations) across the US.

Saline formations

Estimates of how much carbon could be stored in saline formations vary widely; the characteristics of the rock strata and its ability to store CO2 over the long-term are barely known — until recently, such rock held little interest for the oil and gas companies that have conducted most US geological research and therefore only a little information is available. The IPCC believes that carbon sequestration is vital to limiting the impact of CO2 buildup — if we fail to do so, we could see spiking values well in excess of 600 ppm (currently we stand a little over 400 ppm).

BECCS and carbon sequestration

The long-term goal is to sequester up to two gigatons of carbon per year by 2050, though scientists at Stanford have estimated that as much as 10 gigatons of carbon could be sequestered through this method by that point. Carbon sequestration in geological formations isn’t the only option, but it’s one of the few ideas that’s both achievable and reasonably well understood at this point. There are a few technologies being developed that might help us with carbon sequestration, but really there just hasn’t been much research into it yet. Other ideas, like seeding the ocean with iron particles to increase carbon sequestration have problems of their own — locking more CO2 into the depths increases ocean acidification, which is already becoming problematic for a number of species. When the ocean is too acidic, many crustaceans can’t form strong shells — the calcium carbonate that they rely on is in short supply. Coral is also negatively impacted, which reduces habitat and food supply for the species that depend on its abundance. [Read: ‘Supergreen’ hydrogen creation could capture carbon from the air and de-acidify the oceans.] The sheer vastness of the ocean means it may be possible to lock up some carbon in specific areas, but overall, there may not be enough headroom to meaningfully defray the long-term environmental impact of continued fossil fuel use. The alternative is to find a way to sequester carbon geologically — or get used to a world without any ice caps.

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Three Political Paths to Stop Northern Gateway

Federal approval handed huge power to British Columbians. Our job is to get organized.

By Kai Nagata, Today, TheTyee.ca

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Several friends told me this week the Northern Gateway pipeline “finally feels real.” Even people who were cavalier about the inevitability of federal approval described feeling unexpectedly emotional. A few I didn’t even realize had the issue on their radar are suddenly speaking eloquently and passionately — not so much about the details of the proposal, but about the way Ottawa’s decision was carried out.

Enbridge CEO Al Monaco says it will be at least “12 to 15 months” before they’ll be ready to build. With that window in mind, the common question for those who want to stop it is: “How?”

Some are well-positioned to challenge this decision in the courts — First Nations governments best of all. The Crown committed a costly legal error when it left Enbridge to its own devices for so many years, attempting “consultation” deep in unceded territories. Those court cases could last for years and many of us who are not First Nations or trained lawyers will certainly donate to see them succeed.

Some pipeline opponents also promise to physically interfere with construction, should it ever proceed. More blockades like the Unist’ot’en camp may well spring up in the north. Environmental groups are already fundraising to hold workshops on civil disobedience.

Other critics are thinking big-picture about the demand for oil and how to undermine the business case for raw bitumen exports. Whether clean-tech entrepreneurs or climate policy advocates, these groups aim to shift the market conditions that make projects like Northern Gateway profitable in the first place.

Put it this way: there are many ways to stop the pipeline. Some combination of the above would probably stifle Northern Gateway eventually. But British Columbians can’t afford to spend another five years fighting a single project that never should have been proposed in the first place. There’s so much else we need to work on.

I believe the swiftest, most decisive way to stop Enbridge is political — and the most powerful tool most of us have is our vote. That’s why I chose to join Dogwood Initiative. We’re political organizers without partisan baggage. We believe decisions should be made by the people who have to live with them. And we know if First Nations and B.C. voters had a democratic say over this project, Enbridge would be packed up and gone tomorrow.

Three political paths

Tyee columnist Bill Tieleman is right when he writes that a Conservative election loss in 2015 would likely end Enbridge’s pipe dream for good. Opposition leaders Tom Mulcair, Justin Trudeau and Elizabeth May have each promised to cancel the project should their party form government. Supporting their candidates federally is certainly one political path to stopping Northern Gateway. What do we do until then?

Bear in mind our provincial government also has jurisdiction and retains the right to say no. That was made clear in the federal announcement on Tuesday: “The proponent will need to seek various regulatory approvals from the federal government and the governments of British Columbia and Alberta … The Province of British Columbia would be responsible for issuing approximately 60 permits and authorizations.”

Recognize that number? “British Columbia has the power to grant or withhold 60 permits,” Premier Christy Clark told a university audience in Calgary back in 2012. Later that day she told reporters: “If British Columbia doesn’t give its consent to this, there is no way the federal government or anyone else in the country is going to be able to force it through. It just won’t happen.”

Clark is still saying no, for now. Meanwhile, Enbridge’s Al Monaco says “we’re not looking at these conditions as something we’re opposing. These conditions will help us make a better project. It’s up to B.C. to decide whether the conditions are met and it’s up to us to try and close the gap.” Pushing the Clark government toward a final rejection of those permits is the second political path to stopping Enbridge.

That brings us to the third and perhaps least understood course of action. Under a law unique to British Columbia, the people themselves have the right to draft a bill on a matter of provincial jurisdiction. With support from 10 per cent of fellow voters around the province, that bill can be handed over to MLAs to pass into law. For example, a law denying provincial permits to a pipeline that would carry diluted bitumen over hundreds of streams and rivers.

The first major challenge lies in the difficulty of the petition process. Not only must you gather signatures on paper, you have to round up support from 10 per cent of registered voters in every riding in the province. At the bare minimum that’s 320,000 people across all 85 electoral districts — within a three-month deadline.

Assuming canvassing teams pass this Herculean challenge, further pitfalls await. Mr. Tieleman was the strategist behind the Fight HST campaign and probably knows the legislation better than anyone in the province. As he points out, “The government can indeed chose to hold an initiative referendum, but the results are not binding. Or it can simply introduce the bill proposed by the petition into the B.C. legislature, but not even debate it, let alone pass it.”

Tieleman calls the law toothless, fundamentally flawed and designed to fail. Yet he marshalled thousands of volunteers to try it anyway. It begs the question: why bother?

Process versus political reality

The truth is that the initiative to end the harmonized sales tax wasn’t just about the merits of HST versus PST.

As campaign spokesman Bill Vander Zalm wrote in March 2010, “The campaign to defeat the HST has ballooned into something much bigger and even more significant than protesting an unjust, illegal and unethical tax. As profound as those arguments are, there is something deeper and even more powerful afoot. People are rising up to take back their democracy.”

Gordon Campbell didn’t just impose an unpopular tax; he misled the people of British Columbia. He broke a major election promise. Worse, it was later discovered his party planned it that way all along. At that point it doesn’t matter how many loopholes are built into the Recall and Initiative Act, none are big enough to jump through when hundreds of thousands of voters want your hide.

Mr. Tieleman says “Our victory depended on Campbell’s multiple miscalculations, including his decision to hold a binding referendum in 2011.” Tieleman is being modest. Fight HST was designed from the start to put Campbell in checkmate. It ended the premier’s elected career.

The underlying purpose of launching a citizens’ initiative, whether on sales tax or oil tankers, is not only to change legislation. The mechanism itself forces you to build massive, organized political power — the kind no elected official can afford to ignore.

It’s a high mountain to climb. The question is what lies at the top. What motivates people to commit to the journey?

Put it this way: what is the legacy of the HST victory? We switched back to paying PST last year. His Excellency Gordon Campbell is now Canada’s high commissioner in London. And four years after the election that started the whole scandal, Campbell’s successor Christy Clark stormed back to win a stronger majority government.

Where are the boxes and boxes of petition signatures? Presumably safe in a vault at Elections BC. Those people can never be emailed or called, invited to a workshop or asked to donate to a new campaign. Even if they could speak to each other, the threat of the HST has passed. Their affiliation was momentous, but short-lived.

Building beforehand

Here’s where Dogwood’s strategy differs. As of today we have not approached Elections BC to launch a citizens’ initiative. Instead we’re building ahead. We call it a democratic insurance policy in case Premier Clark pulls her own version of the HST flip-flop and gives a green light to Enbridge. The longer that day is delayed, the closer to ready our organizers will be.

So far Clark is standing up to Ottawa, which puts her in line with First Nations and a democratic majority of B.C. voters. That’s good, but we imagine she’s going to come under a lot of pressure to keep the door open for Enbridge. As the company pulls out its chequebook and starts knocking off the NEB’s conditions, we’ll be watching closely to see if Clark’s position shifts. As her own government told the joint review panel at the Enbridge hearings, “‘trust us’ isn’t good enough”.

Here’s where we’re at. In the 48 hours following the federal announcement on Northern Gateway, 48,000 new supporters signed our pledge at LetBCvote.ca. Total signatures now surpass 200,000 — collected in person, online and through cell phones.

We have the benefit of technology that campaigners could only dream of back when the Recall and Initiative Act was introduced in 1995. The other night we signed up our first community hall full of supporters via text message (try it out if you like: text “vote” to 604-265-4967). We’re investing in mapping software to make our teams on the ground more efficient. And social media has extended our reach like never before.

But those bells-and-whistles should not obscure the off-line, social core of the project.

The simple fact is every door we knock on prompts a face-to-face conversation between two neighbours. That in itself is positive. From there, every new signature represents another voter who shares our values — or someone we can help get registered to vote. Every canvassing shift teaches you more about your community. And every few blocks you meet someone who loves the idea so much they want a clipboard too.

The most exciting number to me so far is 7,000. That’s the number of British Columbians who’ve taken the brave step of offering to leave their house so they can talk about democracy with strangers. New volunteers get a phone call from their closest team leader and an invitation to the next local training workshop. (Apologies if it takes us a few days to get to you right now — we’re thrilled by the response but our systems are a little stretched.)

Before the federal announcement, we had teams in 33 ridings. Now powerful allies are stepping forward to say they want to work together to defeat Northern Gateway democratically. We’re in discussions with Unifor, Coastal First Nations and a raft of smaller groups — many of which are already established in their home communities.

Whether they take a formal hand in the initiative preparations or work on parallel projects in complementary ridings, our goal is to form a network of allied organizers across all 85 B.C. ridings.

The citizens’ initiative should be thought of as a last-ditch scenario. A final democratic line of defence if our provincial politicians let us down. But if they hold fast to their rejection of the Enbridge proposal, our training and preparation will not be in vain. As Bill Tieleman points out, there’s a federal election next year. Only one party supports Northern Gateway.  [Tyee]

Kai Nagata is the energy and democracy director of the Dogwood Initiative.

What hit Calgary?

“The frequency with which Canada experiences events such as heavy rainfall of a given intensity (known as the return period), is projected to increase such that an event that occurred on average once every 50 years will be likely to occur about once every 35 years by 2050.”Telling the Weather Story, Insurance Bureau of Canada, 2012

My city, a vibrant place that often transcends the province’s narcissistic oil culture, has had a Manhattan moment.

We thought we were big and powerful and beyond humbling just like New York. But as every true cowboy knows, Mother Nature invariably has the last word.

And so Calgarians are now living a chronicle foretold by climate scientists.

Many once worked at federal agencies that the nation’s federal government ruthlessly axed in an ideological assault on science and reason.

My friends and neighbours have also experienced another extreme weather event that Insurance Bureau of Canada reported a year ago, “will likely result in continued flood risk throughout Alberta.”

Alberta, always a geography of maximum weather, is now climate change central in Canada due to exponential growth in human communities and all in the path of increasing floods, droughts, fires and hail storms.

Bad weather once racked up $100 million worth of damages every year about a decade ago. Today unpredictable events now create half a billion dollars in disasters almost every year.

Yet most Albertans still can’t believe the scale of the multi-billion disaster that has dampened Calgary and environs because affluence tends to dull the senses.

Tragedy, too, breeds its own strange brew of incongruities.

In Calgary a citizen can still down a cappuccino on 17th Ave. while watching fire trucks laden with yellow Zodiacs race to flooded homes just blocks away.

Stunned?

So here’s what happened in the semi-arid Bow River basin (four per cent of Alberta) and it was largely predicted by climate scientists and water experts: An “extreme” weather event fell upon us like some Texas belly washer, and left tens of thousands homeless. Damage will total in the billions.

The speed and scale of the event “stunned” Prime Minister Stephen Harper, a climate change skeptic, and it mortified Premier Alison Redford, whose deficit plagued government hasn’t budgeted for disasters, let alone the future. (One 2011 report catalogued Alberta’s reticence on the issue this way: “Leadership on climate change adaptation from senior levels in all departments is weak.”)

The Great Flood, which punched a giant hole in the TransCanada Highway in Canmore, swelled rivers and undermined infrastructure built for, well, a more stable and reliable climate. The flood also exposed some market-driven deceptions about geography and basic hydrology.

It seems that flood plains will fill with water in oil-rich Alberta, a truth most might find evident but one the province’s one-party government has tried to conceal from the public for years.

A 2006 Provincial Flood Mitigation Report even recommended that the province forbid the selling of flood plains to developers. But the one-party state deep sixed the report for five years and not make it public until 2012.

The freak storm, partly the product of the energy of spend carbon emissions, washed away landmarks, towns, homes, memories, roads, pipelines, wells and bridges. It broke precipitation and stream flow records.

First came scattered rainfall, which saturated the ground in the foothills. Then the skies greyed like a sick man with cancer. The air, redolent of water, hung with a heavy menace.

When the skies opened they delivered buckets of rain that seemed oddly tropical in their intensity.

Along the foothills 80 to 340 mL of water fell in a 24-hour period. Calgary alone broke a record and received 45 mL in a day.

Alberta’s sprawling cities suddenly rediscovered that mountain water moves downhill as fast as torrents ripped through Canmore and Bragg Creek first.

And then the Bow and Elbow rivers swelled, spilling their banks with three times more water than the so-called landmark flood of 2005. (Climate change seems to be all about scoring Olympic records in global weather.)

In it together

Many citizens including myself gathered at off-leash dog park above the Elbow River to gawk and stare at rising waters on Friday morning in Calgary.

It was a remarkable day because the force and volume of water in the city’s rivers brought much of Calgary’s oil economy to a standstill.

Due to road closures and flooding, curious cyclists took to the streets in record numbers too.

Save for the odd reconnaissance helicopter and emergency vehicle sirens, the city seemingly lost its vehicular bustle and grew quiet. The sound of flowing water became, for a day at least, Calgary’s loudest radio station.

The suspension bridge by Sandy Beach crumpled and collapsed in a muddy torrent.

The onlookers photographed the chocolate water of the Elbow with their phones like Japanese tourists as it whooshed its way into city neighborhoods inundating thousands of homes and the Stampede grounds.

Meanwhile the Bow River took on the shape of the Mississippi and shut down the downtown core of the city. Canada’s oil capital could be without power for days if not weeks.

Warnings unheeded 

As I watched with a mixture of sadness and horror (the energy of Mother Nature is unlike any mechanical energy) I recalled a long list of dry climate change reports and emotionless forecasts for Alberta.

In 2005 the Prairie Adaptation Research Collaborative promised warming temperatures, melting glaciers, variable rainfall, changes in stream flows, accelerated evaporation and more extreme events.

In 2006 climate scientist Dave Sauchyn told a Banff audience that “droughts of longer duration and greater frequency, as well as unusual wet periods and flooding” would be the new forecast. Meanwhile researchers documented a 26-day shift in the onset of spring in Alberta over the past century.

Five years later the Bow River Council concluded that “Our rapidly growing population demands much of the land and water. Our climate is changing and the future of our water supplies is uncertain.”

In 2010 the National Roundtable on the Environment and the Economy, an agency that the Harper government killed last year because it didn’t like its messages on climate change, reported that changing precipitation patterns were “the most common gradual, long-term risk from a changing climate identified by Canadian companies.”

In particular oil and gas firms “with operations in Alberta expressed the highest level of concern. A number of them described potential water shortages due to decreased precipitation and runoff as the most significant risk from physical impacts of climate change that they are likely to face.”

In 2011 the NREE published more inconvenient truths in a document called Paying the Price. It concluded that annual cost of flooding in Canada due to climate change could total $17 billion a year by 2050.

It added that “economic and population growth, coupled with anticipated effects of climate change, will impact Canada’s freshwater systems and create new pressures on the long-term sustainability of our water resources.”

Moreover rising temperatures will “affect precipitation patterns and evaporation rates, as well as the frequency, intensity, and duration of extreme weather and climate events like droughts, heat waves and storms.”

A building current

The redundancy of the reports is startling. A 2011 document on climate change’s impact on the Bow River warned that events could be far more severe than modern water management has previously experienced.”

And then came the kicker. In 2012 Insurance Bureau of Canada produced a report by Gordon McBean, an expert on catastrophes. It bluntly warned that Alberta “will be greatly affected by drought and water scarcity under changing climate conditions, and can expect potential increases in hail, storm and wildfire events.” Spring rainfall could increase by 10 to 15 per cent in southern Alberta too.

In addition to changing rainfall patterns, “Retreating glaciers and stream flows may create difficulty in providing potable water to Alberta’s rapidly increasing population, and water scarcity may constrain Alberta’s economic development.”

And the list of warnings and chronicles foretold goes on and on like the Bow River itself.

After Hurricane Sandy pulverized Manhattan last year,  New Yorkers realized that they lived at sea level and were extremely vulnerable to climate change. They also learned that placing electrical stations and emergency equipment in basements of buildings or at street level wasn’t smart thinking.

The city’s state of emergency convinced the governor of New York, Andrew Cuomo, that “anyone who says there hasn’t been a dramatic change in weather patterns is in denial.”

Alberta-weather-cost.jpg

According to a recent Nature commentary by energy analyst Chris Nedler, a Google search now turns up more than one million hits “that mention both ‘Hurricane Sandy’ and ‘renewable energy.’ ”

Calgarians, who are as hardy and distinct as New Yorkers, might react in a similar way after the Great Flood of 2013. They may even reassess their government’s carbon-laden pipeline fantasies as well as the pace and scale of the tar sands.

If nothing else the city’s often arrogant elites have been reminded that province’s Chinese-style economic growth is vulnerable to extreme events. A crowded and overdeveloped province of four million is nowhere near as resilient as a province of one million. (By some estimates the province’s untamed growth could make Alberta a net water and food importer by 2050.)

A Great Summary by Andrew Nikiforuk.

http://thetyee.ca/Opinion/2013/06/24/Calgary-Floods-Climate-Change/

happy-aboriginal-dayCalgary-FloodAlbertans have also learned that climate change delivers two extremes: more water when you don’t need it, and not enough water when you do. The geographically challenged have also become learned, once again, that water travels down hill and even inundates flood plains.

So climate change is not a mirage. Nor is it weird science or tomorrow’s news. It is now part of the flow of daily life.

Moreover there is a steep price to pay for inaction on the destabilizing pollution emitted by our proliferating energy slaves.

Calgary’s moment

Water scientist David Schindler, who has warned repeatedly about the extreme droughts and water scarcity that climate change is bringing to the prairies, summed up the whole messy situation in an email to The Tyee and BBC.

“Costs (from the flooding) will be in the billions, and human error is a good reason why, but for the most part it is due to underestimating and ignoring natural flow patterns, rather than the usual watershed modifications,” wrote Schindler.

“Could the wacky weather be part of what is predicted due to climate warming? Very possibly, but of course it is impossible to say so with any certainty.”

In any case Calgary has had its Manhattan moment.

skeptics of note: Richard Muller

Source:  http://www.nytimes.com/2012/07/30/opinion/the-conversion-of-a-climate-change-skeptic.html?_r=3&pagewanted=all

Papers are at BerkeleyEarth.org: BerkeleyEarth.org.

The Conversion of a Climate-Change Skeptic

By RICHARD A. MULLER

Published: July 28, 2012

CALL me a converted skeptic. Three years ago I identified problems in previous climate studies that, in my mind, threw doubt on the very existence of global warming. Last year, following an intensive research effort involving a dozen scientists, I concluded that global warming was real and that the prior estimates of the rate of warming were correct. I’m now going a step further: Humans are almost entirely the cause.

My total turnaround, in such a short time, is the result of careful and objective analysis by the Berkeley Earth Surface Temperature project, which I founded with my daughter Elizabeth. Our results show that the average temperature of the earth’s land has risen by two and a half degrees Fahrenheit over the past 250 years, including an increase of one and a half degrees over the most recent 50 years. Moreover, it appears likely that essentially all of this increase results from the human emission of greenhouse gases.

These findings are stronger than those of the Intergovernmental Panel on Climate Change, the United Nations group that defines the scientific and diplomatic consensus on global warming. In its 2007 report, the I.P.C.C. concluded only that most of the warming of the prior 50 years could be attributed to humans. It was possible, according to the I.P.C.C. consensus statement, that the warming before 1956 could be because of changes in solar activity, and that even a substantial part of the more recent warming could be natural.

Our Berkeley Earth approach used sophisticated statistical methods developed largely by our lead scientist, Robert Rohde, which allowed us to determine earth land temperature much further back in time. We carefully studied issues raised by skeptics: biases from urban heating (we duplicated our results using rural data alone), from data selection (prior groups selected fewer than 20 percent of the available temperature stations; we used virtually 100 percent), from poor station quality (we separately analyzed good stations and poor ones) and from human intervention and data adjustment (our work is completely automated and hands-off).

In our papers we demonstrate that none of these potentially troublesome effects unduly biased our conclusions.

The historic temperature pattern we observed has abrupt dips that match the emissions of known explosive volcanic eruptions; the particulates from such events reflect sunlight, make for beautiful sunsets and cool the earth’s surface for a few years. There are small, rapid variations attributable to El Niño and other ocean currents such as the Gulf Stream; because of such oscillations, the “flattening” of the recent temperature rise that some people claim is not, in our view, statistically significant. What has caused the gradual but systematic rise of two and a half degrees? We tried fitting the shape to simple math functions (exponentials, polynomials), to solar activity and even to rising functions like world population. By far the best match was to the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice.

Just as important, our record is long enough that we could search for the fingerprint of solar variability, based on the historical record of sunspots. That fingerprint is absent. Although the I.P.C.C. allowed for the possibility that variations in sunlight could have ended the “Little Ice Age,” a period of cooling from the 14th century to about 1850, our data argues strongly that the temperature rise of the past 250 years cannot be attributed to solar changes. This conclusion is, in retrospect, not too surprising; we’ve learned from satellite measurements that solar activity changes the brightness of the sun very little.

How definite is the attribution to humans? The carbon dioxide curve gives a better match than anything else we’ve tried. Its magnitude is consistent with the calculated greenhouse effect — extra warming from trapped heat radiation. These facts don’t prove causality and they shouldn’t end skepticism, but they raise the bar: to be considered seriously, an alternative explanation must match the data at least as well as carbon dioxide does. Adding methane, a second greenhouse gas, to our analysis doesn’t change the results. Moreover, our analysis does not depend on large, complex global climate models, the huge computer programs that are notorious for their hidden assumptions and adjustable parameters. Our result is based simply on the close agreement between the shape of the observed temperature rise and the known greenhouse gas increase.

It’s a scientist’s duty to be properly skeptical. I still find that much, if not most, of what is attributed to climate change is speculative, exaggerated or just plain wrong. I’ve analyzed some of the most alarmist claims, and my skepticism about them hasn’t changed.

Hurricane Katrina cannot be attributed to global warming. The number of hurricanes hitting the United States has been going down, not up; likewise for intense tornadoes. Polar bears aren’t dying from receding ice, and the Himalayan glaciers aren’t going to melt by 2035. And it’s possible that we are currently no warmer than we were a thousand years ago, during the “Medieval Warm Period” or “Medieval Optimum,” an interval of warm conditions known from historical records and indirect evidence like tree rings. And the recent warm spell in the United States happens to be more than offset by cooling elsewhere in the world, so its link to “global” warming is weaker than tenuous.

The careful analysis by our team is laid out in five scientific papers now online at BerkeleyEarth.org. That site also shows our chart of temperature from 1753 to the present, with its clear fingerprint of volcanoes and carbon dioxide, but containing no component that matches solar activity. Four of our papers have undergone extensive scrutiny by the scientific community, and the newest, a paper with the analysis of the human component, is now posted, along with the data and computer programs used. Such transparency is the heart of the scientific method; if you find our conclusions implausible, tell us of any errors of data or analysis.

What about the future? As carbon dioxide emissions increase, the temperature should continue to rise. I expect the rate of warming to proceed at a steady pace, about one and a half degrees over land in the next 50 years, less if the oceans are included. But if China continues its rapid economic growth (it has averaged 10 percent per year over the last 20 years) and its vast use of coal (it typically adds one new gigawatt per month), then that same warming could take place in less than 20 years.

Science is that narrow realm of knowledge that, in principle, is universally accepted. I embarked on this analysis to answer questions that, to my mind, had not been answered. I hope that the Berkeley Earth analysis will help settle the scientific debate regarding global warming and its human causes. Then comes the difficult part: agreeing across the political and diplomatic spectrum about what can and should be done.

Richard A. Muller, a professor of physics at the University of California, Berkeley, and a former MacArthur Foundation fellow, is the author, most recently, of “Energy for Future Presidents: The Science Behind the Headlines.”

A version of this op-ed appeared in print on July 30, 2012, on page A19 of the New York edition with the headline: The Conversion of a Climate-Change Skeptic.