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Weird weather: Seeing global warming’s fingerprints

A new scientific report finds man-made climate change played some role in two dozen extreme weather events last year but not in a few other weird weather instances around the world.

An annual report released by the National Oceanic and Atmospheric Administration found climate change was a factor in 24 of 30 strange weather events.

They include 11 cases of high heat, as well as unusual winter sunshine in the United Kingdom, Alaskan wildfires and odd “sunny day” flooding in Miami.

The study documented climate change-goosed weather in Alaska, Washington state, the southeastern United States, Canada, Europe, Australia, China, Japan, Indonesia, Sri Lanka, the western north Pacific cyclone region, India, Pakistan, Egypt, Ethiopia and southern Africa.

“It has to be measureable. It has to be detectable. There has to be evidence for it and that’s what these papers do,” said NOAA scientist Stephanie Herring, co-editor of the report.

In six cases — including cold snaps in the United States and downpours in Nigeria and India — the scientists could not detect climate change’s effects. Other scientists, though, disputed that finding for the cold snap that hit the Northeast.

Herring highlighted the Miami flooding in September 2015. Because of rising sea levels and sinking land, extremely high tides flooded the streets with 22 inches of water.

“This one is just very remarkable because truly, not a cloud in the sky, and these types of tidal nuisance flooding events are clearly become more frequent,” she said.

The report also found an increase in tropical cyclone activity and strength in the western Pacific can be blamed partly on climate change and partly on El Nino, the now-gone natural weather phenomenon. But similar storm strengthening hasn’t increased noticeably around the United States yet, said study co-editor Martin Hoerling, a NOAA scientist.

The report was published in the Bulletin of the American Meteorological Society. Using accepted scientific techniques, 116 scientists from around the world calculated whether the odds of the extreme weather events were increased by global warming. They based their calculations on observed data, understanding of the physics of the climate and computer simulations — techniques that the National Academy of Sciences said were valid earlier this year.

Columbia University meteorology professor Adam Sobel, who was on the national academy panel but not part of this report, praised the NOAA study but noted it wasn’t comprehensive. It picked only certain but not all weather extremes to study.

For the February 2015 Northeast cold snap, other scientists have connected the polar vortex pushing south to shrinking ice in the Arctic Ocean.

Judah Cohen, seasonal forecasting chief at Atmospheric Environmental Research in Lexington, Massachusetts, said he even predicted the 2015 polar vortex because of the low sea ice. He said the same thing is happening with the bitter cold hitting the U.S. this week.

NOAA’s Hoerling said the research found a connection between the shrinking ice and the polar vortex but didn’t see one causing the other.

On the web

Bulletin of the American Meteorological Society.

Warm ocean ‘blob’ facilitated vast toxic algae bloom

A new study finds that unusually warm Pacific Ocean temperatures helped cause a massive bloom of toxic algae that closed lucrative fisheries from California to British Columbia and disrupted marine life from seabirds to sea lions.

Scientists linked the large patch of warm ocean water, nicknamed the “blob,” to the vast ribbon of toxic algae that flourished in 2015 and produced record-breaking levels of a neurotoxin that is harmful to people, fish and marine life.

The outbreak of the toxin domoic acid, the largest ever recorded on the West Coast, closed razor clam seasons in Washington and Oregon and delayed lucrative Dungeness crab fisheries along the coast. High levels were also detected in many stranded marine mammals.

“We’re not surprised now having looked at the data, but our study is the first to demonstrate that linkage,” said Ryan McCabe, lead author and a research scientist at the University of Washington’s Joint Institute for the Study of the Atmosphere and Ocean. “It’s the first question that everyone was asking.”

McCabe and his co-authors explain how the toxic algae bloom thrived in their study published in the journal Geophysical Research Letters.

Seasonal algae blooms are common each year along the West Coast, but most are not toxic. The scientists found that the algae bloom was dominated by a single species called “Pseudo-nitzschia australis” that is highly toxic.

The algae survived and took advantage of warm, nutrient-poor conditions set up by the patch of water that was warmer at the surface than normal.

Coastal upwelling last spring — a seasonal event that brings nutrient-rich, cooler waters up from the deep ocean — provided nutrients for the algae to bloom into a large population fairly quickly at sea. Finally, a series of late spring storms delivered the bloom to the coast.

“While temperature isn’t everything, it’s serving as a decent proxy,” said McCabe. “We think there’s a linkage between toxic events along our coast and climate variability indices.”

The blob was a one-time event that was not due to global warming, “but we are looking at this event as a potential window into the future as what conditions could look like,” McCabe said.

Kathi Lefebvre, a co-author and marine biologist at NOAA’s Northwest Fisheries Science Center, said the bloom resulted in the highest levels of domoic acid contamination in the food web ever recorded for many species.

Domoic acid accumulates in anchovies, sardines and other small fish as well as shellfish that eat the algae.

Marine mammals and fish-eating birds in turn can get sick from eating the contaminated fish. In people, it can trigger amnesic shellfish poisoning, which can cause permanent loss of short-term memory in severe cases.

Sea lions in California commonly experienced seizures, a common sign of domoic acid poisoning, during harmful algae blooms along that state’s coast. But 2015 was the first year that such harmful effects were documented as far north as Washington state, scientists said.

“This is an eye-opener for what the future may hold as ocean conditions continue to warm globally,” Lefebvre said.

‘Hot, wet and wild’ 2016 weather as US has hottest June

America’s warm, wild and costly weather broke another record with the hottest June, federal meteorologists say. And if that’s not enough, they calculated that 2016 is flirting with the U.S. record for most billion-dollar weather disasters.

The month’s average temperature in the Lower 48 states was 71.8 degrees, 3.3 degrees above normal, surpassing the Dust Bowl record set in 1933 by a couple tenths of a degree, the National Oceanic and Atmospheric Administration reported Thursday. Every state in the nation was warmer than normal in June, with Utah and Arizona having their hottest Junes.

“2016 has been hot, wet and wild for the contiguous U.S.,” NOAA climate scientist Jake Crouch said Thursday.

The nation had its third hottest first half of the year. June’s record heat is from a combination of natural variability and long-term global warming, Crouch said. Records go back to 1895.

But there’s been a wet and wild aspect of the year, too. So far, NOAA calculates that there have been eight billion-dollar weather disasters in the first half of this year, not counting the West Virginia flooding, which is still being calculated. They’ve been a combination of severe storms with tornadoes and heavy rains and downpours that cause damaging flooding. Seven of those have hit Texas.

NOAA calculates billion-dollar disasters , adjusting for inflation, to show trends in the most extreme and damaging weather. Since 1980, the U.S. has averaged five billion-dollar disasters a year, but in the last five years the country has averaged nearly 11 a year. There were eight in 2015. The record is 16 different billion-dollar disasters in 2011.

“The main lesson is that it shows us how vulnerable we are to climate change,” Texas A&M climate scientist Andrew Dessler said in an email. “People frequently think that, ‘Oh, we’ll just adapt to climate change.’ But we’re learning that it’s going to be a lot harder than people realize to do that. How do you adapt to the amount of rain that West Virginia got?”

 

Earth sizzles to 13th-straight month of record heat

Earth sizzled to its 13th-straight month of record heat in May, but it wasn’t quite as much of an over-the-top scorcher as previous months, federal scientists say.

Record May heat, from Alaska to India and especially in the oceans, put the global average temperature at 60.17 degrees Fahrenheit (15.65 degrees Celsius), according to NOAA. That’s 1.57 degrees (.87 degrees Celsius) above the 20th-century average, according to the National Oceanic and Atmospheric Administration.

There’s still a good chance that June will break records even as El Nino, one of two main reasons for record heat, dissipates, scientists say. And the U.S. Southwest is in the midst of an historic heat wave.

Tomorrow’s forecast high for Phoenix is 120 degrees, and temperatures are expected to remain above 110 degrees there for at least the next seven days. Palm Springs, California, should reach 121 on Monday. The thermometer will hover around 110 degrees all of next week in Las Vegas.

Last month, India recorded a record high temperature of 123.8 Fahrenheit, beating a 60-year-old record.

Excessive heat is the No. 1 weather-related killer in the United States, including Wisconsin. During the record heat wave in the summer of 1995, 145 people in the state died of prolonged exposure to heat and humidity, making it the top weather-related killer in Wisconsin since it became a state in 1848, according to NOAA.

Seven hundred people died in Chicago during the same heat wave. An August, 2003, heat wave in Europe killed an estimated 50,000 people.

The NOAA’s July through September forecast is for hotter-than-average temperatures in the entire United States except a tiny circle of southeastern Texas.

“We’re in a new neighborhood now as far as global temperature,” said Deke Arndt, NOAA’s climate monitoring chief. “We’ve kind of left the previous decade behind.”

But it’s not quite as broiling as it has been. May only broke the record — set in 2015 — by .04 degrees. It’s the first time since November that a month wasn’t a full degree Celsius (1.8 degrees Fahrenheit) hotter than the 20th-century average. March and February this year were 2.2 degrees Fahrenheit above normal.

“It is slightly off from the kind of unprecedented large global temperatures we’ve seen in the last five to seven months,” Arndt says.

Arndt, like nearly every major climate scientist, says the record warm temperatures are due to a strong El Nino placed on top of man-made global warming from heat-trapping gases that come from the burning of fossil fuels.

The El Nino has just dissipated and forecasters expect its cooler flip side, La Nina, to kick in soon, which should keep global temperatures a bit lower than they’ve been, but still warmer than 20th-century average, Arndt said

But that may not be quite enough to keep 2016 from being the third straight record hot year, Arndt says. That’s because so far, 2016 is averaging 55.5 degrees (13.06 degrees Celsius), which beats the previous January to May record set last year by 0.43 degrees.

Jonathan Overpeck, a climate scientist at the University of Arizona, just came back from India and its record-breaking heat wave in time for potential record breaking heat in parts of Arizona.

“Thirteen months of consecutive record breaking heat is really unprecedented, and it’s yet another visceral glimpse of what is yet to come as the planet warms up even a lot more,” Overpeck said in an email. “No doubt about it, the planet is warming fast and we’re feeling the impacts.”

Study: US oil field source of global uptick in ethane

An oil and natural gas field in the western United States is largely responsible for a global uptick of the air pollutant ethane, according to a new study.

The team led by researchers at the University of Michigan found that fossil fuel production at the Bakken Formation in North Dakota and Montana is emitting roughly 2 percent of the ethane detected in the Earth’s atmosphere.

Along with its chemical cousin methane, ethane is a hydrocarbon that is a significant component of natural gas. Once in the atmosphere, ethane reacts with sunlight to form ozone, which can trigger asthma attacks and other respiratory problems, especially in children and the elderly. Ethane pollution can also harm agricultural crops. Ozone also ranks as the third-largest contributor to human-caused global warming after carbon dioxide and methane.

“We didn’t expect one region to have such a global influence,” said Eric Kort, lead author of the study and an assistant professor of climatic science at the University of Michigan in Ann Arbor.

The study was launched after a mountaintop sensor in the European Alps began registering surprising spikes in ethane concentrations in the atmosphere starting in 2010, following decades of declines. The increase, which has continued over the last five years, was noted at the same time new horizontal drilling and hydraulic fracturing techniques were fueling a boom of oil and gas production from previously inaccessible shale rock formations in the United States.

Searching for the source of the ethane, an aircraft from the National Oceanic and Atmospheric Administration in 2014 sampled air from directly overhead and downwind of drilling rigs in the Bakken region. Those measurements showed ethane emissions far higher than what was being reported to the government by oil and gas companies.

The findings solve an atmospheric mystery — where that extra ethane was coming from, said Colm Sweeney, a study co-author from the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder.

The researchers said other U.S. oil and gas fields, especially the Eagle Ford in Texas, are also likely contributing to the global rise in ethane concentrations. Ethane gets into the air through leaks from drilling rigs, gas storage facilities and pipelines, as well as from intentional venting and gas burnoffs from extraction operations.

“We need to take these regions into account because it could really be impacting air quality in a way that might matter across North America,” Kort said.

Helping drive the high emission levels from the Bakken has been the oil field’s meteoric growth. Efforts to install and maintain equipment to capture ethane and other volatile gases before they can escape have lagged behind drilling, said North Dakota Environmental Health Chief Dave Glatt.

Glatt’s agency has stepped up enforcement efforts in response. Last year, the state purchased a specialized camera that can detect so-called fugitive gas emissions as they escape from uncontained oil storage tanks, leaky pipelines, processing facilities and other sources.

“You’re able to see what the naked eye can’t and it reveals emissions sources you didn’t know where there,” Glatt said. “It’s a game changer. A lot of the companies thought they were in good shape, and they looked through the camera and saw they weren’t.”

Regulators at the Environmental Protection Agency were reviewing the study’s results. Spokeswoman Laura Allen said Friday that new clean air rules recently announced by the Obama administration to curb climate-warming methane leaks from oil and gas drilling operations should also help address the harmful ethane emissions.

There are other ways ethane gets into the atmosphere — including wildfires and natural seepage from underground gas reserves. But fossil fuel extraction is the dominant source, accounting for roughly 60 to 70 percent of global emissions, according to a 2013 study from researchers at the University of California.

February’s record heat like something ‘out of a sci-fi movie’

February’s record heat left federal scientists struggling to find words, describing temperatures as “astronomical,” “staggering” and “strange.” They warned that the climate may have moved into a new and hotter neighborhood.

This was not just another of the drumbeat of 10 straight broken monthly global heat records, triggered by a super El Nino and man-made global warming. February 2016 obliterated old marks by such a margin that it was the most above-normal month since meteorologists started keeping track in 1880, according to the National Oceanic and Atmospheric Administration.

The old record was set just last December and the last three months have been the most above-normal months on record, said NOAA climate scientist Jessica Blunden. And it’s not just NOAA. NASA, which uses different statistical techniques, as well as a University of Alabama Huntsville team and the private Remote Sensing System team, which measure using satellites, also said February 2016 had the biggest departure from normal on record.

NOAA said Earth averaged 56.08 degrees (13.38 degrees Celsius) in February, 2.18 degrees (1.21 degrees Celsius) above average, beating the old record for February set in 2015 by nearly six-tenths of a degree (one-third of a degree Celsius). These global heat figures had federal scientists grasping for superlatives.

“The departures are what we would consider astronomical,” Blunden said. “It’s on land. It’s in the oceans. It’s in the upper atmosphere. It’s in the lower atmosphere. The Arctic had record low sea ice.”

“Everything everywhere is a record this month, except Antarctica,” Blunden said. “It’s insane.”

In the Arctic, where sea ice reached a record low for February, land temperatures averaged 8 degrees above normal (4.5 degrees Celsius), Blunden said. That’s after January, when Arctic land temperatures were 10.4 degrees above normal (5.8 degrees Celsius).

Worldwide, the record heat made February 2016 warmer than about 125 of the last 136 Marches.

It was also the warmest winter — December through February — on record, beating the previous year’s record by more than half a degree (0.29 degrees Celsius).

Georgia Tech climate scientist Kim Cobb said she normally doesn’t concern herself much with the new high temperature records that are broken regularly.

“However,” she added in an email,” When I look at the new February 2016 temperatures, I feel like I’m looking at something out of a sci-fi movie. In a way we are: it’s like someone plucked a value off a graph from 2030 and stuck it on a graph of present temperatures. It is a portent of things to come, and it is sobering that such temperature extremes are already on our doorstep.”

Scientists at NOAA’s National Centers for Environmental Information in Asheville, North Carolina, were astonished by the “staggering” numbers, said Deke Arndt, the centers’ global monitoring chief.

“Usually these are monthly reminders that things are changing,” Arndt said. “The last six months have been more than a reminder, it’s been like a punch in the nose.”

NASA’s chief climate scientist Gavin Schmidt usually discounts the importance of individual record hot months, but said this month was different, calling it “obviously strange.”

This was due to the long-term warming from heat-trapping gases and the powerful El Niño, so these types of record heat numbers will continue for a few more months, but probably will not be a permanent situation, Schmidt said in an email.

But others were not so sure, including Arndt, who compared it to moving into a new hotter neighborhood.

“We are in a new era,” Arndt said. “We have started a new piece of modern history for this climate.”

Jason Furtado, a meteorology professor at the University of Oklahoma who wasn’t part of any of the government teams, simply wrote in an email: “Welcome to the new normal.

 

Online:

NOAA: www.ncdc.noaa.gov

Follow Seth Borenstein at http://twitter.com/borenbears and his work can be found at http://bigstory.ap.org/content/seth-borenstein

 

 

Study: Warming climate will wreak havoc on world economy

With each upward degree, global warming will singe the economies of three-quarters of the world’s nations and widen the north-south gap between rich and poor countries, according to a new economic and science study.

Compared to what it would be without more global warming, the average global income will shrivel 23 percent at the end of the century if heat-trapping carbon dioxide pollution continues to grow at its current trajectory, according to a study published this week in the scientific journal Nature.

Some countries, like Russia, Mongolia and Canada, would see large economic benefits from global warming, the study projects. Most of Europe would do slightly better, the United States and China slightly worse. Essentially all of Africa, Asia, South America and the Middle East would be hurt dramatically, the economists found.

“What climate change is doing is basically devaluing all the real estate south of the United States and making the whole planet less productive,” said study co-author Solomon Hsiang, an economist and public policy professor at the University of California Berkeley. “Climate change is essentially a massive transfer of value from the hot parts of the world to the cooler parts of the world.”

“This is like taking from the poor and giving to the rich,” Hsiang said.

Lead author Marshall Burke of Stanford and Hsiang examined 50 years of economic data in 160 countries and even county-by-county data in the United States and found what Burke called “the goldilocks zone in global temperature at which humans are good at producing stuff” — an annual temperature of around 13 degrees Celsius or 55.4 degrees Fahrenheit, give or take a degree.

For countries colder than that economic sweet spot, every degree of warming heats up the economy and benefits. For the United States and other countries already at or above that temperature, every degree slows productivity, Burke and Hsiang said.

The 20th-century global average annual temperature is 57 degrees, or 13.9 degrees Celsius, according to the National Oceanic and Atmospheric Administration. Last year — the hottest on record — was 58.24 degrees and this year is almost certain to break that record, according to NOAA. Burke and Hsiang use different population-weighted temperature figures than NOAA calculates.

But the U.S. economy is humming despite the heat. When asked how that can be so, Burke said there were many factors important for growth beyond just temperature. He said one year’s temperature and economic growth in one nation isn’t telling. Instead, he and Hsiang looked at more than 6,000 “country-years” to get a bigger picture.

Burke compared the effect of global warming on economies to a head wind on a cross-country airplane flight. The effects at any given moment are small and seemingly unnoticeable but they add up and slow you down.

While it is fairly obvious that unusual high temperatures hurt agriculture, past studies show hot days even reduce car production at U.S. factories, Burke said.

“The U.S. is really close to the global optimum,” Burke said, adding that as it warms, the U.S. will fall off that peak. The authors calculate a warmer U.S. in 2100 will have a gross domestic product per person that’s 36 percent lower than it would be if warming stopped about now.

But because the U.S. is now at that ultimate peak, there’s greater uncertainty in the study’s calculations than in places like India, Pakistan, Vietnam, Nigeria and Venezuela where it’s already hot and there’s more certainty about dramatic economic harm, Hsiang said.

The authors’ main figures are based on the premise that carbon dioxide emissions will continue to rise at the current trajectory. But countries across the world are pledging to control if not cut carbon pollution as international leaders prepare for a summit on climate change in Paris. If the current pledges are kept, the warming cost in 2100 will drop from 23 percent to 15 percent, Burke said.

Gary Yohe, an environmental economist at Wesleyan University in Connecticut, praised the study as significant and thorough, saying Burke and Hsiang “use the most modern socio-economic scenarios.” But Richard Tol, an economist at the University of Sussex in England, dismissed the study as unworthy to be published in an economics journal, saying “the hypothesized relationship is without foundation.”

Other experts found good and bad points, with MIT’s John Reilly saying it will spark quite a debate among economists.

Earth in July hottest on record

July’s average temperature was 61.86 degrees Fahrenheit, beating the previous global mark set in 1998 and 2010 by about one-seventh of a degree, according to figures released Thursday by the National Oceanic and Atmospheric Administration. That’s a large margin for weather records, with previous monthly heat records broken by a 20th of a degree or less.

“It just reaffirms what we already know: that the Earth is warming,” said NOAA climate scientist Jake Crouch. “The warming is accelerating and we’re really seeing it this year.”

NOAA records go back to 1880. Separate calculations by NASA and the Japanese weather agency also found July 2015 to be a record.

The first seven months of 2015 were the hottest January-to-July span on record, according to NOAA. The seven-month average temperature of 58.43 degrees is 1.53 degrees warmer than the 20th-century average and a sixth of a degree warmer than the old record set in 2010.

Given that the temperatures have already been so high already – especially the oceans, which are slow to cool – NOAA climate scientist Jessica Blunden said she is “99 percent certain” that 2015 will be the hottest on record for the globe. The oceans would have to cool dramatically to prevent it, and they are trending warmer, not cooler, she said.

Crouch, Blunden and other scientists outside of the government said these temperatures are caused by a combination of man-made climate change and a strong, near-record El Nino. An El Nino is a warming of the equatorial Pacific Ocean that alters weather worldwide for about a year.

The oceans drove the globe to record levels. Not only were the world’s oceans the warmest they’ve been in July, but they were 1.35 degrees warmer than the 20th-century average.

The heat hit hard in much of Europe and the Middle East. It was the hottest July on record in Austria, where records go back to 1767. Parts of France had temperatures that were on average 7 degrees above normal and temperatures broke 100 in the Netherlands, which is a rarity. And an Iranian city had a heat index (the “feels like” temperature) of 165 degrees, which was still not quite record.

Nine of the 10 hottest months on record have happened since 2005, according to NOAA. Twenty-two of the 25 hottest months on record have occurred after the year 2000. The other three were in 1998 and 1997.

This shows that despite what climate change doubters say, there is no pause in warming since 1998, Blunden said.

It doesn’t matter if a month or a year is No. 1 or No. 2 or No. 5 hottest on record, said University of Georgia climate scientist Marshall Shepherd.

“The records are getting attention but I worry the public will grow weary of reports of new records each month,” Shepherd said in an email. “I am more concerned about how the Earth is starting to respond to the changes and the implications for my children.”

On the Web…

NOAA on July records: http://www.ncdc.noaa.gov/sotc/summary-info/global/201507.

Study rebuts doubters: No stop, no slowdown of global warming

Global warming has not stopped or even slowed in the past 18 years, according to a new federal study that rebuts doubters who’ve claimed that that heating trends have paused.

Scientists at the National Oceanic and Atmospheric Administration readjusted thousands of weather data points to account for different measuring techniques through the decades. Their calculations show that since 1998, the rate of warming is about the same as it has been since 1950: about two-tenths of a degree Fahrenheit a decade.

The so-called hiatus has been touted by non-scientists who reject mainstream climate science. Those claims have resonated; two years ago, the United Nation’s Intergovernmental Panel on Climate Change felt the need to explain why the Earth was not heating up as expected, listing such reasons as volcanic eruptions, reduced solar radiation and the oceans absorbing more heat.

“The reality is that there is no hiatus,” said Tom Karl, director of the National Centers for Environmental Information in Asheville, North Carolina. He is the lead author of a study published Thursday in the peer-reviewed journal Science

One key to claims of a hiatus is the start date: 1998. That year there was a big temperature spike; some of the following years were not as hot, though even hotter years followed in 2005, 2010 and 2014, according to NOAA, NASA and temperature records kept in England and Japan. This year is on pace to break last year’s global heat record.

Scientists keep updating the way they measure Earth’s temperatures. This study focuses on the effects of the way ocean temperatures are taken. The old way, going back generations, is with ships. Sometimes people would dip a bucket in the way; other times they’d measure water that came into the engine. They also did it at various times of day.

The new way is on buoys at the same time of day. Karl said the buoy measurements are more accurate, but can’t be compared directly to the ship measurements for a trend without making adjustments, because that would be comparing apples and oranges. So to come up with a trend using comparable numbers, NOAA increases the buoy temperatures a bit.

A few years ago NOAA made similar adjustments to make land temperatures more comparable decade-to-decade. But that also caused some non-scientists who reject climate change to cry tampering.

Several outside scientists contacted by The Associated Press said the new and previous adjustments are sound. Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, said the new work was “good and careful analysis” but only confirms what most scientists already knew, that there was no such hiatus.

A few years ago, a group out of University of California Berkeley – funded in part by the Charles Koch Foundation, whose founder is a major funder of climate doubter groups and the tea party- took what was initially billed as a skeptical look at the previous NOAA data. But they pronounced the earlier adjustments legitimate. The same scientists now say the new NOAA adjustments are also proper.

“NOAA is confirming what we have been saying for some time that the `hiatus’ in global warming is spurious,” Berkeley team chief and physicist Richard Muller said in an email. Muller said global warming continues but in “many fits and spurts.”

John Christy of the University of Alabama Huntsville, one of the minority of scientists who dispute the magnitude of global warming, said the Karl paper “doesn’t make sense” because satellite data show little recent warming. “You must conclude the data were adjusted to get this result” of no warming pause, Christy wrote in an email. “Were the adjustments proper? I don’t know at this point.”

Others who reject warming, especially non-scientists, point to satellite records by Remote Sensing Systems that appear to show no change in temperature since 1998. Satellites measure a different part of Earth’s atmosphere than ground and ocean monitors that NOAA, NASA and others use.

Carl Mears, senior research scientist for RSS, said those rejecting climate change based on his work or any one dataset are wrong and “seek to deny the reality of human-induced climate change by grasping at straws.” Mears said the overall data consistently show long-term global warming and that it really hasn’t stopped recently. The NOAA adjustments make sense, he said.

Karl said NOAA didn’t adjust datasets in the Arctic, where it is warming even faster, because there is a lack of reliable long-term records to compare. Had NOAA made those adjustments, the recent warming trend would be slightly larger, he said.

On the Web …

Science: http://sciencemag.org

NOAA National Centers for Environmental Information: http://www.ncdc.noaa.gov