Climate Change Blogs

Arctic Sea Ice May Reach Second-Lowest Extent on Record This Month

Published: September 3, 2015
A burst of late-season loss over the last several weeks has put the Arctic Ocean’s ice cover within reach of the lowest extent observed in any year except 2012. The extent values tracked by the National Snow and Ice Data Center, or NSIDC (see Figure 1), show that 2015 has caught up to several other recent years in the amount of ice depleted, and is poised to surpass 2011 and 2007 if the rapid loss continues. The milestone is a timely one, given this week’s historic Alaskan visit by President Barack Obama.

NSIDC reviewed the near-term outlook for sea ice in an update posted on Wednesday: “There is still a possibility that 2015 extent will be lower than 4.3 million square kilometers, the third lowest sea ice extent, surpassing the 2011 sea ice extent minimum, and a small chance of surpassing 2007, resulting in the second-lowest daily minimum. This assumes that we continue to have sea ice loss rates at least as fast as those of 2010. This was indeed the case for the final ten days of August 2015.”

As explained by NSIDC with a swiss-cheese analogy, sea ice extent refers to the amount of ocean covered by at least 15 percent ice concentration (the dimensions of the slice of cheese), whereas sea ice area is the literal amount of ocean covered by ice, not counting the holes. Arctic ice normally reaches its maximum extent in March and its minimum in September. The ice extent drops in spring and summer largely as a result of melting (from below and above), though it can also be influenced by compaction (which pushes broken-up areas of ice together, reducing the total ice extent). Another factor is a pattern of atmospheric pressure called the Arctic Dipole, which favors Asia-to-Europe cross-polar flow that can push ice out the Fram Strait into the North Atlantic, hastening ice depletion.

Figure 1. Sea ice extent across the Arctic Ocean for the period August-November, 1979-2015. This year’s extent was just over 4.6 million square kilometers on September 2, and dropping rapidly, with only the 2012 curve falling much lower. Nine of the 10 lowest extent values have occurred within the last decade. Image credit: NSIDC.

There’s still plenty of darkness and cold air to foster ice-cover regrowth across most of the Arctic each winter, but the summer minima have plummeted in recent decades (see Figure 1). With just weeks left before net ice expansion resumes, it’s all but impossible for 2015 to catch up to 2012. That year saw the lowest extent since satellite records began in 1979 (3.41 million square km, or about 50% below the typical minimum observed in the 1980s and 1990s). However, a minimum in the vicinity of 4.2 to 4.3 million sq km seems within reach. That would be well below the average value of 4.8 million sq km predicted by an array of 38 participants in the latest monthly Sea Ice Outlook produced by the Sea Ice Prediction Network. By that time this forecast was issued (August 20), Arctic ice extent had come off near record-low values for late spring, recovered somewhat by early summer—thanks in part to a cold June across the Arctic, with relatively little melting--and dipped again in August, with fairly steady losses through the month. Then came a surprisingly strong cyclone that developed across the Beaufort Sea last week. High winds and seas from that storm helped weaken a large arm of multi-year ice extending from the central Arctic into the Beaufort Sea. The storm also brought punishing waves and erosion to the Alaskan coast near Barrow (see Figure 2).

Figure 2. High surf batters the coast near downtown Barrow, Alaska, on August 27, 2015. Image source: Barrow Sea Ice Webcam, tweeted by Brian Brettschneider

Figure 3. This intense surface cyclone disrupted a large chunk of Arctic sea ice that extended from the Central Arctic into the Beaufort Sea. Analysis for 0000 GMT on August 27, 2015, shows sea level pressure (in green); potential temperature at the tropopause, a marker of upper-level energy that can help foster surface cyclones (in black); and the extent of Arctic sea ice (grey shading, with concentration fraction shown by the bar at right). A corresponding animation shows the sequence of events beginning on August 16 and segues into a model prediction from August 2 to September 9. Image credit: Steven Cavallo, University of Oklahoma.

What’s ahead this month and beyond?
“It is still pretty stormy over the Arctic,” said Steven Cavallo, a University of Oklahoma meteorologist who specializes in polar weather. Cavallo has researched tropopause polar vortices (TPVs) and their relationship to surface cyclones. “There are a lot of TPVs around, meaning the potential for surface cyclone formation is high, so I think the forecast sensitivity is very high right now and there could still be some significant ice loss.” Recent model runs have flip-flopped in predicting additional strong cyclones over the Arctic over the next few days. Cavallo hypothesizes this could be related to the difficult-to-predict effects of tropical cyclones recurving into the polar jet stream. At the Arctic Sea Ice Blog and Forum, there’s been a lot of conversation along these lines. “People on the forum are speculating on and off about a 'train' of cyclones, either Atlantic or Pacific, injecting heat and moisture into the Arctic,” said blog/forum founder Neven Acropolis in an email. Two good places to follow the dialogue are “The 2015 melting season” thread and Acropolis’s own excellent posts.

Figure 4. Sea ice concentration for September 1, 2015, as calculated by the National Snow and Ice Data Center. Areas shaded in lighter blue denote reduced concentration (area) within the overall bounds of ice extent. Image credit: NSIDC.

The ice that’s managing to persist across the Arctic this summer doesn’t look especially healthy. Polar climate specialist Jennifer Francis (Rutgers University) calls out the warning signs conveyed in the most recent ice concentration image from NSIDC (see Figure 4, at right). “Much of the ice that's left is either slushy, severely broken up, or covered in melt ponds,” Francis noted. Depletion is especially large on the Pacific side of the Arctic, she added, which recent work suggests may favor a severe winter in parts of eastern North America. Much research in the last few years by Francis and others has worked to draw connections between Arctic sea ice loss, high-latitude warming, and midlatitude winter weather. A new entry in this mini-discipline is a paper published last week in Nature Geoscience that links two modes of warm Arctic weather to subsequent winter cold downstream across East Asia and North America.

The power of this year’s still-strengthening El Niño event may be enough to swamp whatever influence the decline of Arctic sea ice might have on the upcoming winter across North America. Sea-surface temperatures (SSTs) are cooling over the western tropical Pacific in tandem with the building El Niño warmth over the eastern tropical Pacific. A number of studies (nicely summarized by Daniel Swain at California Weather Blog) suggest that the western-Pacific cooling will help lead to more storminess over the Gulf of Alaska, which in turn could finally erode the persistently warm SSTs and the “ridiculously resilient ridge” of high pressure that have prevailed in that area for most of the last two years. If so, a pathway will be carved for the classic El Niño signature of very mild winter temperatures across most of Canada and the northern United States, in line with the latest seasonal forecasts from NOAA. If, instead, we see a third consecutive winter of unusual cold across the U.S. Midwest and Northeast, it’ll be a strong sign that another player is onstage. Judah Cohen (Atmospheric and Environmental Research) bases his North American winter forecasts in part on the apparent relationship between low Arctic sea ice extent and cold Northern Hemisphere winters. “I really do think that this could be a very interesting winter and could be very informative on the interplay of tropical vs. Arctic forcing,” said Cohen in an email. “Can the Arctic, as a forcing agent of mid-latitude weather, finally step out out of the shadow of the tropics or not?”

Figure 5. Both the Arctic and Antarctic rack up more than 12 million square klilometers of sea ice extent each winter, but the summer ice depletion is greater in the Antarctic, where the ice sits at lower latitudes. Image credit: The Cryosphere Today/University of Illinois at Urbana-Champaign.

Why it matters
Although a coating of ice does return to most of the Arctic Ocean each winter, the persistence of ice through the summer is a vital part of the region’s ecosystem. Polar bears, ringed seals, and other wildlife use the ice as a platform for hunting prey and raising their young. Many indigenous residents of the lands circling the Arctic have also relied on the presence of year-round ice for centuries. The picture is far different at the other end of the world: instead of being surrounded by ocean, the South Pole lies at the heart of the landmass of Antarctica. Sea ice in this hemisphere develops on the fringes of Antarctica, which puts it at a lower latitude than most Arctic sea ice. As a result, nearly all of the ice that forms each winter around Antarctica melts back each summer. The average wintertime extent of ice around Antarctica has actually grown slightly in recent years, for reasons not fully understood. This is often falsely presented as “balancing” the loss of Arctic sea ice, but the Arctic loss is far more substantial than the Antarctic gain, and much more important to regional climate, ecology, and economy. Ice-free navigation is now once again possible in the Arctic along the coast of Canada (the southern route of the fabled Northwest Passage), and has been open for over a month along the coast of Russia (the Northeast Passage or Northern Sea Route.) Mariners have been attempting to sail these passages since 1497; the first time they were open for ice-free navigation without an icebreaker was in 2005 for the Northeast Passage and 2007 for the Northwest Passage. The continuing erosion of summer ice cover in the Arctic has stoked interest in expanding industrial activity across the region, including oil and gas development--an ironic turn of events, given the role of fossil-fuel-produced greenhouse gases in the worldwide warming of recent decades.

Tropical Atlantic: Tenacious Fred hangs on
Tropical Storm Fred has been in “never say die” mode, hanging on as a minimal tropical storm on Thursday morning as it drifted across the eastern Atlantic. New thunderstorms blossomed on the east side of Fred’s circulation center on Wednesday night into Thursday, despite stout wind shear of more than 35 mph. By midday Thursday, only a much smaller patch of convection was located just north of Fred’s exposed center. The shear is expected to increase, and the National Hurricane Center expects Fred to become a remnant low by Friday. NHC is mentioning the possibility, though, that Fred could spring back to life in five days, when the storm will encounter lower wind shear and anomalously warm waters of 27.5°C (82°F) over 500 miles southwest of the Azores Islands.

New tropical wave moving off the coast of Africa has potential to develop
A strong tropical wave with plenty of spin and heavy thunderstorm activity will move off the coast of Africa by Thursday night, and has the potential to become a tropical depression early next week as the storm moves west at 15 - 20 mph. The 00Z Thursday (8 pm EDT Wednesday) runs of two of our top three models for predicting tropical cyclone genesis, the GFS and European models, predicted that this new wave would become a tropical depression in the waters southwest of the Cape Verde islands by Monday. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave the wave 2-day and 5-day odds of development of 10% and 40%, respectively. The tropical Atlantic is relatively moist, has the highest sea surface temperatures of the year, and is expected to have low to moderate wind shear, conditions which favor development. The wave should take about 7 - 8 days to make it to the Lesser Antilles Islands.

Figure 6.Typhoon Kilo and Hurricanes Ignacio and Jimena, all captured in this infrared image from the GOES-West satellite at 1330 GMT (9:30 am) Thursday, September 3, 2015. Image credit: NOAA/NHC and Michael Lowry, The Weather Channel.

Pacific continues to bristle with tropical cyclones
The Northeast Pacific has a new named system, Tropical Storm Kevin. As of 11 am EDT Thursday, Kevin’s top sustained winds had increased to 50 mph. Kevin is expected to live out the rest of its life below hurricane strength over open water before increasing amounts of shear and mid-level dry air take their toll. Some moisture associated with Kevin will be working its way into Colorado and New Mexico through Saturday ahead of a large upper-level trough approaching the region, enhancing shower and thunderstorm activity there. In the Central Pacific, powerful Hurricane Jimena is very slowly weakening but remains a high-end Category 2 as it embarks on a broad cyclonic loop well northeast of Hawaii over the next few days. We’ll have to keep an eye on Jimena in the long range, as the recent runs of the GFS and European models bring Jimena back toward Hawaii from the northeast late next week, still as a tropical storm. Such a scenario might be dismissed out of hand in any other year, but with SSTs so warm in the Central and Northeast Pacific, Jimena could conceivably remain over waters at or above the threshold of 26°C (79°F) over most or all of such a trek. Meanwhile, Hurricane Ignacio, now a Category 1 storm north of Hawaii, is also weakening but remains impressively well-structured, with extensive spiral banding. Ignacio is on track to plow into the Gulf of Alaska as a powerful extratropical storm by early next week. En route, Ignacio will pass over unusually warm waters along the way, with sea-surface temperatures up to 3-4°C (5.4-7.2°F) above average (though eventually too cool to support Ignacio as a tropical cyclone).

Ultra-resilient Typhoon Kilo is now in its 14th day as a tropical cyclone, including a long spell as a major hurricane. Kilo is predicted to steadily reintensify over the next 3-4 days, again reaching Category 4 strength by Tuesday as it moves on a westward loop that will likely take it several hundred miles north of Wake Island. In the long range, Kilo may pose a threat to Japan.

We’ll be back with our next update on Friday.

Bob Henson and Jeff Masters

U.S. Wildfires 2015: Are The Worst Yet To Come?

Published: September 2, 2015
Thus far, 2015 has been one of the worst U.S. wildland fire seasons since modern records began. More than 8.2 million acres have burned across the nation as of September 1, an area larger than Massachusetts and Rhode Island combined. Across the last ten years, that’s the largest amount of fire-scorched U.S. acreage for the January-August period, and it’s close to 50% above the decadal year-to-date average. We are well ahead of the pace set in 2007, when 9,328,045 acres burned, the highest annual total in records going back to 1960.

Figure 1. Flames from a backfire operation burn behind an emergency vehicle near the Rocky Fire on August 3, 2015, near Clearlake, California, north of San Francisco. Some 3,000 firefighters battled the Rocky Fire, which burned more than 80,000 acres and destroyed almost 100 residences and outbuildings. Image credit: Justin Sullivan/Getty images.

There’s a more complex story hiding behind these factoids. Certainly there have been some intense and large fires across the Pacific Northwest, pumping out smoke that’s reddened skies and clotted lungs across large swaths of the nation. But up until August, the main factor behind this year’s large wildfire acreage (as explained by Tom Yulsman at Discover’s ImaGeo blog) was the extent of fire in Alaska. More than 5.1 million acres had burned across the state as of September 1, most of it by midsummer. With Alaska’s fire activity now slowing down, the state’s total affected acreage will likely rank second behind 2004, when a total of 6,590,140 Alaskan acres went up in flames.

It was clear by early summer that the Pacific Northwest was in line for a potentially rough fire season, with long streches of record spring and summer heat following a winter with record-low snowpack. Simply having a parched landscape doesn’t automatically translate into big fire, though. If strong, dry winds are absent; if fires aren’t triggered by lightning and/or human activity; and/or if firefighters manage to tamp down fires quickly, then the potential for disaster may go unrealized. Wildfires didn’t begin taking full advantage of the Pacific Northwest’s primed-for-fire condition until mid-August, when the Okanogan Complex roared to life across north-central Washington. Now the state’s largest assemblage of wildfires on record, the Okanogan Complex (40 percent contained as of Tuedsay) has destroyed more than 170 homes.

Figure 2.The Significant Wildland Fire Potential Outlook for September 2015 shows above-normal risk across parts of four western states, as well as a small part of central Texas. Image credit: National Interagency Coordination Center.

On August 13, officials upgraded the National Preparedness Level for wildland fire to category 5, the highest, meaning that multiple major fires have the potential to exhaust all of the nation’s firefighting resources. This is the first category-5 ranking since a week-long stretch in August 2013, and the fifth such period in the last ten years. Cooler temperatures should continue to tamp down the fire risk in Alaska this month, but it’s far too soon for other western states to rest easy. The latest monthly outlooks for wildland fire potential, issued on Monday by the National Interagency Coordination Center, show an above-normal risk of significant wildfire in September across eastern Washington, northeast Oregon, and far northwest Montana, as well as the Sierra Nevada and coastal mountains south of the Bay Area in California. By October, the risk is expected to return to near normal over the Pacific Northwest and central California, but the highly populated belt of Southern California is still targeted for above-normal risk.

Why fall is the most-feared time for wildfire in California
California’s Mediterranean climate means that rainfall is focused in the period from late fall into spring, with the landscape then getting progressively drier until the next wet season kicks in. This sets up prime conditions for wildland fire during the typically warm, dry weather of September and October, sometimes goosed by strong offshore winds (dubbed the Santa Ana wind in the L.A. area). Late October 1991 brought the horrific Oakland hills firestorm, which destroyed more than 2,800 homes and killed 25 people, and Southern California’s record-setting wildfire seasons of 2003 and 2007 both peaked in October.

Figure 3. Meg Tallberg (left), whose home was not damaged by fire, offers her support to neighbor and friend Jenny Fratis (right), whose house (background) was destroyed in the Witch Fire, as residents returned to Rancho Bernardo in California's San Diego County on 25 October, 2007. Image credit: Robyn Beck/AFP/Getty Images.

This year, California is entering fire season after four years of drought, culminating in what’s been the warmest year for California in more than a century of recordkeeping. Although some unusual summer rains have provided dabs of relief across the far southeastern desert, much of the landscape across central and southern California remains tinder-dry. Some 46% of the state is now in exceptional drought, the highest ranking assigned by the National Drought Mitigation Center in its weekly U.S. Drought Monitor. That’s down a bit from 58% at this time a year ago, but the impacts of long-term drought in the hardest-hit areas remain severe. In August, a study from the University of California, Davis, estimated that the ongoing drought will cost California about $2.7 billion in 2015. Several intense, destructive fires have already struck the state, including the small but frightening, interstate-jumping North Fire east of Los Angeles in mid-July and the huge Rocky and Jerusalem Fires north of San Francisco in late July/early August.

The main questions awaiting the West’s fire-prone areas this autumn--questions that forecasters can’t answer with confidence--is how often and where windy frontal systems and/or strong offshore flow will materialize. NOAA’s seasonal outlook for September through November maintains above-average temperatures throughout the West Coast states, with precipitation below average in the Pacific Northwest and above average over southern California. The strengthening El Niño gives SoCal a good chance at above-average rains this winter, but the heaviest Niño-related rains often don't arrive till December/January.

Figure 4. While in Alaska, WU art director Lauren Moyer captured the not-so-common sight of a virtually cloud-free Mount Denali on August 3, 2015. In the foreground is a WU personal weather station, MEVCA2. Image credit: wunderphotographer moyerdestroyer.

Climate change and wildfire risk
One of the key points made by President Barack Obama in his visit to Alaska this week (including Wednesday’s scheduled stop north of the Arctic Circle, the first ever by a president in office) is the role of human-induced climate change in exacerbating wildfire risk across the state. In a speech delivered Monday in Anchorage, Obama noted: “Alaska’s fire season is now more than a month longer than it was in 1950. At one point this summer, more than 300 wildfires were burning at once.” The lengthening fire season in Alaska reflects a global trend: a new open-access analysis published in Nature Comunications in July found that 25% of Earth’s vegetated surface saw fire seasons grow longer from 1979 to 2013 by an average of close to 20%.

Figure 5. Areas that have experienced changes in the frequency of long fire weather seasons (at least one standard deviation above the historical average) during the period 1996-2013 compared with 1979–1996. Reds indicate areas where fire weather seasons have lengthened or long fire weather seasons have become more frequent. Blues indicate areas where fire weather seasons have shortened or long fire weather seasons have become less frequent. Image credit: Figure 3(b), “Climate-induced variations in global wildfire danger from 1979 to 2013,” W. Matt Jolly et al., Nature Communications 2013.

Alaska has warmed more quickly than the rest of the nation over the last 60 years, with annual average temperatures in Alaska climbing by about 3.0°F over the period from 1949 to 2014. The warming has come in phases, according to the Alaska Climate Research Center, with temperatures spiking in the 1970s and then plateauing at a “new normal” for several decades before a new level of warmth was hit in 2014, continuing into this year. The period Jan-July 2015 was Alaska’s second warmest in 91 years of recordkeeping, according to NOAA’s National Centers for Environmental Information. The U.S. National Climate Assessment, published in 2014, had this to say about Alaska’s evolving climate and fire risk: “Both wetland drying and the increased frequency of warm dry summers and associated thunderstorms have led to more large fires in the last ten years than in any decade since record-keeping began in the 1940s….More extensive and severe wildfires could shift the forests of Interior Alaska during this century from dominance by spruce to broadleaf trees for the first time in the past 4,000 to 6,000 years.”

Figure 6. Annual average temperature across Alaska, 1949 – 2014. Image credit: Alaska Climate Research Center.

Wildfires are the complex product of many variables, including forest management, fire suppression, temperatures and moisture, ignition sources, and firefighting practices. Prior to European settlement, gigantic fires were part of the natural ecosystems across much of North America. In a blog post from 2013, Andrew Revkin discusses the historical context of U.S. fire suppression and its role in helping lay the groundwork for today’s megafires. Whatever factors have led to the forests we have today, their ability to burn intensely is being stoked by rising temperatures that intensify the impacts of naturally occurring drought, a point illustrated vividly this year from California to Washington and emphasized in several recent studies (including this one, published just this week in Geophysical Research Letters). There will be some inevitable randomness in the final, fateful steps (weather events, arsonists, etc.) that lead from a particular parched landscape to a devastating fire. We’re very unlikely to see the entire West in flames anytime soon (thankfully!), but it’s reasonable to expect that heat unprecedented in modern times and dried-out vegetation will sometimes lead to fires more intense and/or widespread than ever before seen by residents of a given area. With ever-larger numbers of Americans choosing to live amid western forests, and cities such as Oakland and Los Angeles adjoining fire-prone areas, the risks to life and property will only rise with time.

Figure 7. It’s a hurricane! It’s a typhoon! It’s both! Dan Lindsey (CIRA) posted this tongue-in-cheek analysis of Kilo, using a visible image from Japan’s Himiwari-8 satellite, as the storm straddled the International Date Line on September 1, 2015. Hurricanes are reclassified as typhoons when they move west across the Date Line. The Sydney Morning News asked whether Kilo should be called a “hurriphoon” or a “typhane.” Kilo was officially reclassified from Hurricane Kilo to Typhoon Kilo at 0600 GMT on September 1. Image credit: RAMMB/CIRA/JMA.

Tropics calming down
After weeks of hyperactivity, the Northern Hemisphere tropics are beginning to calm down for the time being. The 00Z Thursday morning run of the GFS model was not predicting any new tropical cyclones to develop anywhere in the world during the next seven days, though the European model was showing possible development next week of a tropical wave expected to come off the coast of Africa this Friday. This wave is expected to move westwards at about 15 mph towards the Lesser Antilles Islands; NHC did not mention this wave in their 8 am EDT Wednesday Tropical Weather Outlook. Tropical Storm Fred continues to weaken in the far eastern North Atlantic; likewise, Hurricane Jimena in the Northeast Pacific and Hurricane Ignacio in the Central Pacific are gradually spinning down. Only Typhoon Kilo is expected to resurge over the next several days. Currently almost stationary just west of the International Date Line, Kilo should gradually accelerate westward across warm waters south of a subtropical ridge, gaining strength along the way and perhaps reaching Category 4 status once again by the end of the week. Today (September 2) is Kilo’s 13th day as a tropical cyclone, and this morning's run of the GFS model predicted that Kilo would remain a tropical cyclone for at least nine more days. According to the National Hurricane Center, the longest-lived tropical cyclone in the satellite era is Hurricane/Typhoon John, which was tracked for 31 days during August and September 1994.

WU contributor Phil Klotzbach has a new post on the recent frenzy of North Central Pacific activity; see also his two-part entry on record-setting action across the Northern Hemisphere as a whole, posted on August 25 and August 28.

We’ll be back with another post on Thursday.

Bob Henson and Jeff Masters

July 2015: Warmest Month on Record Globally

Published: August 20, 2015
The Atlantic and Pacific tropics were buzzing with activity on Thursday (see bottom of this post for a very brief update), but Thursday brought other big news as well: July 2015 was the warmest single month in 1627 months of global records that go back to January 1880, said NOAA's National Centers for Environmental Information (NCEI). The globally averaged temperature above both land and ocean surfaces was 1.46°F (0.81°C) ahead of the 20th-century average. This trumps the record for any month that was set in July 1998, surpassing that value by 0.08°F (0.14°C). On average, July is the warmest month of the year globally, tpyically driven by midsummer conditions across the Northern Hemisphere’s extensive land areas. However, according to NOAA, record warmth across much of the Pacific and Indian oceans played a major role in July’s new global record. NASA also rated July 2015 as the warmest July on record. July 2015's warmth makes the year-to-date period (January - July) the warmest such period on record, according to both NOAA and NASA. A potent El Niño event in the Eastern Pacific that crossed the threshold into the "strong" category in early July continues to intensify, and strong El Niño events release a large amount of heat to the atmosphere, typically boosting global temperatures by at least 0.1°C. This extra bump in temperature, when combined with the long-term warming of the planet due to human-caused emissions of heat-trapping gases like carbon dioxide, makes it extremely likely that 2015 will be Earth's second consecutive warmest year on record.

Figure 1. Departure of temperature from average for July 2015, the warmest single month for the globe since record keeping began in 1880. Large areas of record warmth were analyzed across many parts of the Indian and Pacific oceans, as well as in northern South America, southeast Africa, and parts of southern Europe. Image credit: National Centers for Environmental Information (NCEI) .

Global satellite-measured temperatures in July 2015 for the lowest 8 km of the atmosphere were the 10th warmest in the 37-year record, according to the University of Alabama Huntsville (UAH). The lowest 8 km of the atmosphere heats up dramatically in response to moderate to strong El Niño events, with a time lag of several months--as occurred during the El Niño events of 1998 and 2010. Thus, we should see Earth's lower atmosphere temperature hit record levels late this year and/or early in 2016.

Deadliest weather disaster of July 2015: monsoon floods in Asia
The deadliest weather-related disaster of July 2015 was flooding in Asia due to the annual monsoon, which claimed over 200 lives in Pakistan, Myanmar, Afghanistan, Bangladesh, Vietnam, India, and China. Severe flooding in these countries continued during the first ten days of August, bringing the total monsoon death toll to over 400, as reported by Bob Henson in his August 11 post.

Figure 2. Navigating a flooded area of Peshawar, Pakistan, on July 26, 2015. Torrential rains and floods in Pakistan left 36 dead and affected more than 250,000 people, disaster management officials said July 25, with swollen rivers and water channels damaging hundreds of villages. Photo credit: A Majeed/AFP/Getty Images.

Two billion-dollar weather disasters in July 2015 in China
Two billion-dollar weather-related disasters hit the Earth last month, both in China, according to the July 2015 Catastrophe Report from insurance broker Aon Benfield: Typhoon Chan-hom ($1.6 billion in damage) and flooding July 20 - 24 that caused $1.2 billion in damage. With twelve billion-dollar weather disasters so far in 2015, Earth is on pace for its lowest number of such disasters since 2004, when sixteen occurred.

Disaster 1. Typhoon Chan-hom made landfall about 80 mi south-southeast of Shanghai, China on July 11, killing 16 people and doing at least $1.5 billion in damage. The typhoon did another $100 million in damage to Guam, Japan, Taiwan, and Korea. In this image, we see people watching huge waves from Chan-hom pounding Wenling, in east China's Zhejiang province, on July 10, 2015. Image credit: STR/AFP/Getty Images.

Disaster 2. Heavy rainfall in China from July 20 - 24 killed 28 people and did $1.2 billion in damage. More than 238,000 residents were evacuated as floods and landslides destroyed 7,770 homes and damaged 35,100. In this picture, we see vehicles stranded on a flooded road in Wuhan, Hubei Province of China, on July 23, 2015, when 160.2 millimeters (6.31") hit the city. This was their heaviest daily rainfall since 1998, according to Changjiang Times. Image credit: ChinaFotoPress/Getty Images.

Arctic sea ice falls to 8th lowest July extent on record
Arctic sea ice extent during July 2015 was the 8th lowest in the 36-year satellite record, according to the National Snow and Ice Data Center (NSIDC). A large area of high pressure set up shop north of Alaska, and a strong area of low pressure formed over Northeastern Eurasia. The circulation around these features brought sunny skies and a warm flow of air into the Arctic that led to rapid ice loss. This Arctic Dipole pattern also occurred in all the summer months of 2007, and helped support the record 2007 summer reduction in sea ice extent. (Note that the record was beaten in 2012, a year that did not feature an Arctic Dipole pattern.) The Arctic Dipole pattern diminished in early August 2015, but substantial melting has continued into the middle of the month.

Notable global heat and cold marks set for July 2015
Hottest temperature in the Northern Hemisphere: 52.8°C (127.0°F) at Mitribah, Kuwait, July 30
Coldest temperature in the Northern Hemisphere: -22.5°C (-8.5°F) at Summit, Greenland, July 30
Hottest temperature in the Southern Hemisphere: 37.6°C (99.7°F) at Floriano, Brazil, July 10
Coldest temperature in the Southern Hemisphere: -80.2°C (-112.4°F) at Dome A, Antarctica, July 2

Major stations that set (not tied) new all-time heat or cold records in July 2015
Akkuduk (Kazakhstan) max. 46.8°C July 1
Boulogne sur Mer (France) max. 35.4C° July 1
Melun (France) max. 39.4°C July 1
Dieppe (France) max. 38.3°C July 1
Urumita (Colombia) max. 42.2°C July 1
Dzhusaly (Kazakhstan) max. 46.2°C July 2
Volkel (Netherlands) max. 36.9°C July 2
Twenthe (Netherlands) max. 36.1°C July 2
Leeuwarden (Netherlands) max. 34.0°C July 2
Valledupar-Villa Rosa (Colombia) max. 42.4°C July 3
Bad Lippspringe (Germany) max. 37.9°C July 4
Giessen (Germany) max. 38.1°C July 4
Repelon (Colombia) max. 40.9°C July 4
Frankfurt (Germany) max. 39.0°C July 5
Ohringen (Germany) max. 38.5°C July 5
Wurzburg (Germany) max. 38.6°C July 5
Kiztingen (Germany) max. 40.3°C July 5, New national record high for Germany
Kahl (Germany) max. 39.8°C July 5
Bad Durkheim (Germany) max. 39.7°C July 5
Neunkirchen (Germany) max. 39.2°C July 5
Hannover City (Germany) max. 39.0°C July 5
Aigle (Switzerland) max. 36.1°C July 5
Gerona Airport (Spain) max. 41.3°C July 5
Gerona St Daniels (Spain) max. 42.2°C July 5
Cienfuegos (Cuba) max. 37.0°C July 6
Barcelonette (France) max. 34.3°C July 6
Mende (France) max. 36.1°C July 6
Gap (France) max. 36.9°C July 6
Saint-Martin-d’Heres (France) max. 40.7°C July 7
Lezigneux (France) max. 39.9°C July 7
Embrun (France) max. 36.7°C July 7
St Etienne (France) max. 41.1°C July 7
Sainte-Leocadie (France) max. 35.4°C July 7
Grenada Airport (Spain) max. 43.1°C July 7
Grenada City (Spain) max. 43.9°C July 7
Lerida (Spain) max. 43.1°C July 7
Zaragoza (Spain) max. 44.5°C July 7
Geneva (Switzerland) max. 39.7°C July 7
Nyon/Changins (Switzerland) max. 38.0°C July 7
Payerne (Switzerland) max. 37.9°C July 7
Neuchatel (Switzerland) max. 37.8°C July 7
Fribourg (Switzerland) max. 36.6°C July 7
Neuenburg (Switzerland) max. 37.8°C July 7
Wynau (Switzerland) max. 37.2°C July 7
Evolene (Switzerland) max. 28.4°C July 7
Plaffeien (Switzerland) max. 32.0°C July 7
La Fretaz (Switzerland) max. 29.9°C July 7
Oberstdorf (Germany) max. 35.6°C July 7
Innsbruck City (Austria) max. 38.2°C July 7
Qaanaaq (Greenland/Denmark) max. 20.4°C July 8
Ardebil (Iran) max. 40.2°C July 10
Jucaro (Cuba) max. 36.8°C July 10
Riohacha (Colombia) max. 40.6°C July 13
Yuzawa (Japan) max. 36.8°C July 13
Washikura (Japan) max. 29.0°C July 13
Tajima (Japan) max. 34.8°C July 13
Niitsu (Japan) max. 37.9°C July 13
Ogata (Japan) max. 38.3°C July 13
Uozu (Japan) max. 37.9°C July 13
Nanao (Japan) max. 37.4°C July 13
Yamada (Japan) max. 37.5°C July 14
Kasenuma (Japan) max. 36.7°C July 14
Marumori (Japan) max. 37.6°C July 14
Yanagawa (Japan) max. 39.1°C July 14
Kawauchi (Japan) max. 35.7°C July 14
Ononimachi (Japan) max. 35.8°C July 14
Buzaubaj (Uzbekistan) max. 48.2°C July 14
Limoges Airport (France) max. 37.3°C July 16
Grazzanise (Italy) max. 39.8°C July 17
Split Airport (Croatia) max. 39.4°C July 18
Krems (Austria) max. 38.3°C July 19
Senj (Croatia) max. 39.7°C July 22
Rab (Croatia) max. 39.3°C July 22
Zadar Airport (Croatia) max. 39.0°C July 22
Zavizan (Croatia) max. 28.3°C July 22
Ronchi dei Legionari (Italy) max. 39.2°C July 22
Aviano (Italy) max. 38.3°C July 22
Vsetin (Czech Republic) max. 36.8°C July 22
Osako (Japan) max. 36.4°C July 22
Esashi (Japan) max. 37.2°C July 22
Kanayama (Japan) max. 36.1°C July 22
Altai (China) max. 39.5°C July 22
Hoboksar (China) max. 37.7°C July 22
Kaba He (China) max. 41.0°C July 22
Korla (China) max. 40.5°C July 24
Jucaro (Cuba) max. 37.0°C July 28
Contramaestre (Cuba) max. 38.2°C July 29
Isabel Rubio Airport (Cuba) max. 36.3°C July 29
Indio Hatuey (Cuba) max. 38.1°C July 30
Kirkuk (Iraq) max. 50.0°C July 30
Najaf (Iraq) max. 51.5°C July 30
Kanaqin (Iraq) max. 52.0°C July 30
Salahaddin (Iraq) max. 41.1°C July 31
Meigetsu (Japan) max. 37.8°C July 31
Vize Island (Russia) max. 9.2°C July 31

New all-time national and territorial heat records set or tied in 2015
As of August 14, 2015, ten nations or territories tied or set all-time records for their hottest temperature in recorded history in 2015, and one (Israel) set an all-time cold temperature record. For comparison, only two nations or territories set all-time heat records in 2014, and nine did in 2013. The most all-time national heat records held by any year is nineteen in 2010. Most nations do not maintain official databases of extreme temperature records, so the national temperature records reported here are in many cases not official. I use as my source for international weather records researcher Maximiliano Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records. Wunderground's weather historian Christopher C. Burt maintains a database of these national heat and cold records for 235 nations and territories on's extremes page. Here are the all-time national or territorial heat and cold records set so far in 2015:

Hong Kong set its national heat record on August 9, when the mercury hit 37.9°C (100.2°F) at Happy Valley.
Germany set a new national heat record of 40.3°C (104.5°F) twice this year: on July 5 and on August 7, at the Kitzingen station in Bavaria.
Vietnam tied its national heat record of 42.7°C (108.9°F) at Con Cuong on May 30.
Palau tied its national heat record of 34.4°C (94.0°F) at Koror Airport on May 14.
Venezuela set a new national heat record of 43.6°C (110.5°F) at Coro on April 29.
Laos tied its national heat record of 42.0°C (107.6°F) at Thakhek on April 20.
Ghana set a new national heat record of 43.3°C (109.9°F) at Navrongo on April 10. This is the third time this year Ghana has tied or set a new all-time heat record.
Cocos Islands (Australian territory) tied their all-time heat record with 32.8°C (91.0°F) on April 8.
Equatorial Guinea set a new national heat record of 35.5°C (95.9°F) at Bata on March 17.
Wallis and Futuna Territory (France) set a new territorial heat record with 35.5°C (95.9°F) on January 19 at Futuna Airport.

Israel set a new national cold record of -14.2°C (6.4°F) at Merom Golan on January 10.

Special Mentions:
Antarctica set a new heat record for its mainland of 17.5°C (63.5°F) at Esperanza Base on March 24. Previous record: 17.4°C (63.3°F) at Marambio Base, set the previous day. The World Meteorological Organization (WMO) has appointed a committee to study this event and determine if this represents an official record for the continent. Note that this is a record for mainland Antarctica, not a territorial or continental record. The all-time maximum record for the continent and territory of Antarctica is 19.8°C (67.6°F) on January 30, 1982, in Signy Island, South Orkney, an island group located about 450 miles northeast of the tip of the Antarctic Peninsula, the northernmost portion of mainland Antarctica. Geologically, the South Orkney are on the Antarctic plate, and politically, they are part of Antarctica. This record was improperly listed as a territorial record for Antarctica in May's global summary.

Switzerland had its highest reliably measured temperature on record in Geneva on July 7, when the mercury hit 103.5°F (39.7°C). The only higher temperature ever measured in the country was a 106.7°F (41.5°C) reading on August 11, 2003 at Grono. As reported at the Swiss news site, this old record was achieved "using an old measurement technique of weather huts, which generally recorded temperatures a few degrees higher than modern instruments." Weather records researcher Maximiliano Herrera agrees that this year's 39.7°C reading in Geneva is the highest reliably measured temperature ever in Switzerland, though the August 11, 2003 temperature at Grono was probably warmer (near 40°C), after correcting for the known problems with the site.

Samoa was originally listed by Mr. Herrera as tying its national heat record with 36.5°C (97.7°F) on January 20 at Asau, but a subsequent review of the record revealed possible issues with the measurement equipment, so this record is dubious.

Kudos also to Mr. Herrera for supplying the data for the "Notable global heat and cold marks set for July 2015" and "Major stations that set (not tied) new all-time heat or cold records in July 2015" sections.

Danny strengthens slightly; 93C likely to become Hurricane Kilo and approach Hawaii
Tiny Hurricane Danny continues to gradually strengthen in the central Atlantic. At 5:00 p.m. EDT, Danny’s top sustained winds were up to 80 mph. Danny was still located far out to sea—more than 1000 miles east of the Windward Islands, moving west-northwest at just 10 mph—and there are no major changes to the outlook for Danny from our post this morning. Meanwhile, Invest 93C has been upgraded to Tropical Depression 3 in the central Pacific, and the Central Pacific Hurricane Center projects TD 3-C to become Hurricane Kilo by Saturday, perhaps curving toward the western Hawaiian islands as a Category 2 hurricane by Monday. We’ll have a full update on both systems by 1 PM ET Friday. See also Steve Gregory’s update from earlier this afternoon.

Jeff Masters and Bob Henson

Record Ocean Temperatures Threaten Hawaii's Coral Reefs

Published: July 24, 2015
Record warm sea surface temperatures in Hawaii's waters threaten to bring a second consecutive year of record coral bleaching to their precious coral reefs this summer. According to NOAA, ocean temperatures in the waters near and to the south of the Hawaiian Islands were 1 - 2°C (1.8 - 3.6°F) above average in June, which was the warmest these waters have been since record keeping began over a century ago. With the waters surrounding Hawaii expected to warm to their highest values of the summer by September, and likely remain 1 - 2°C above average, NOAA's Coral Reef Watch has placed the islands under a Coral Bleach Watch, and their experimental coral bleaching forecast gives a 50 - 90% chance that Hawaii will experience "Level 2" thermal stress this summer--the highest category of danger, likely to result in widespread coral bleaching and mortality. The record warm ocean temperatures are due to a strong El Niño event that is pushing large amounts of record-warm water into the Central Pacific, in combination with the steady rise in ocean temperatures due to global warming. Mass coral die-offs commonly occur during strong El Niño events; the United Nations Environmental Program found that 16% of the worlds coral reefs were effectively lost during a nine-month coral bleaching episode associated with the 1997 - 1998 record-strength El Niño event. With this year's El Niño event likely to be almost as strong as the 1997 - 1998 one, coral reefs are going to take a beating again.

Figure 1. NOAA's experimental coral bleaching forecast gives a 50 - 90% chance that Hawaii will experience Satellite Bleaching Alert Level 2 thermal stress this summer--the highest category of danger, likely to result in widespread coral bleaching and mortality. El Niño conditions have produced an extremely warm band of water from the central equatorial Pacific to the South American coast, and Level 2 thermal stress has already been reached in the Gilbert, Phoenix, and Northern Line Islands in Kiribati, as well as in Micronesia, the Howland and Baker Islands, and to the east in the Galápagos.

Figure 2. Unusually warm waters are also in place along the northern coast of Cuba and in the Bahamas, and NOAA's experimental coral bleaching forecast gives about a 70% chance coral reefs in these waters will experience Satellite Bleaching Alert Level 2 thermal stress this summer--the highest category of danger, likely to result in widespread coral bleaching and mortality.

Second consecutive year of severe coral bleaching in Hawaii
Hawaii's reefs are already reeling from their worst coral bleaching event in recorded history in 2014, when record warm ocean temperatures caused 50 - 70% of the corals sampled in Northeast Oahu's Kāneʻohe Bay to bleach. When the sea surface temperature is 1°C warmer than the highest monthly mean temperature corals usually experience, coral polyps will expel the symbiotic algae that live in their tissues, exposing the white skeleton underneath, resulting in a white "bleached" appearance. Death can result if the stress is high and long-lived. In Hawaii's waters, corals cannot tolerate water temperatures above 83°F (28.3°C) for multi-week periods without suffering bleaching. Corals typically recover from mild bleaching, gradually recovering their color by repopulating their algae. However, if the bleaching is severe or prolonged, individual polyps or whole colonies will die. With Hawaii likely to undergo a second consecutive year of record warm waters and coral bleaching in 2015, widespread mortality in many of Hawaii's coral reefs is possible, particularly around the Big Island.

Figure 3. During June 2015, the ocean areas near and to the south of Hawaii were at their warmest levels since record keeping began in 1880. Image credit: National Centers for Environmental Information (NCEI) .

Could a hurricane help?
When hurricanes and tropical storms churn the waters, they upwell large amounts of cooler waters from the depths that can cool the surface waters, potentially reducing the thermal stress on coral reefs. The heavy rains from the storm can also potentially cause cooling. This occurred in the Virgin Islands in 2010, when Hurricane Earl and Hurricane Otto helped relieve a potentially dangerous coral bleaching episode (Figure 4.) So, should Hawaii hope for a hurricane this September to help save its coral reefs? Well, be careful what you wish for. Hurricanes cause damage to reefs. Following Tropical Storm Iselle, which hit the Big Island of Hawaii on August 7, 2014, with 60 mph winds, researchers at the University of Hawaii, Hilo documented that one coral reef on the Big Island (the Wai`ōpae tide pools) suffered physical damage from pounding waves that broke up to 18% of the coral colonies of one species of coral with long slender branches--cauliflower coral. Other corals suffered lesser damage, 0 - 10% breakage. In addition, these corals were subjected to sewage contamination due to damage of cesspools and septic tanks.

Figure 4. Mean daily temperatures (on left Y-axis) with standard error collected at reef-depth (26'-58') monitoring sites on St. John US Virgin Islands, and total daily rainfall (on right Y-axis) from August through October 2010 from Newfound, Haulover, Tektite, Yawzi and Mennebeck Reefs in the Virgin Islands. Image credit: Rafe Boulon, Resource Management Chief, Virgin Islands National Park.

Long term outlook for world's coral reefs: bleak
The large amount of carbon dioxide humans have put into the air in recent decades has done more than just raise Earth's global temperature--it has also increased the acidity of the oceans, since carbon dioxide dissolves in sea water to form carbonic acid. The oceans are acidifying faster than at any time in the past 300 million years. Corals have trouble growing in acidic sea water, and the combined effects of increasing ocean temperatures, increasing acidity, pollution, and overfishing have reduced coral reefs globally by 19 percent between 1950 - 2008. Another 35 percent could disappear in the next 40 years, even without the impact of climate change, according to a report released in October 2010 by the World Meteorological Organization and the Convention on Biological Diversity.

Coral expert J.E.N. Veron, former chief scientist of the Australian Institute of Marine Science, had this to say in an excellent interview he did with Yale Environment 360 in 2010: "the science is clear: Unless we change the way we live, the Earth's coral reefs will be utterly destroyed within our children's lifetimes...Reefs are the ocean's canaries and we must hear their call. This call is not just for themselves, for the other great ecosystems of the ocean stand behind reefs like a row of dominoes. If coral reefs fail, the rest will follow in rapid succession, and the Sixth Mass Extinction will be upon us--and will be of our making."

Figure 5. An example of coral bleaching that occurred during the record-strength 1997-1998 El Niño event. Image credit: Craig Quirolo, Reef Relief/Marine Photobank, in Climate, Carbon and Coral Reefs

Jeff Masters
Categories:Climate Change

Fewer but Stronger Global Tropical Cyclones Due to Ocean Warming

Published: July 23, 2015
Global ocean temperatures hit their warmest levels in recorded history last month. Since hurricanes are heat engines which extract heat energy from the oceans and convert it to the kinetic energy of the storms' winds, we should be concerned about the potential for hurricanes to be stronger as a result of global warming. Indeed, the observed 0.3°C (0.5°F) warming of Earth's oceans over the past 30 years has made more energy available to hurricanes, says a new study published in May in Nature Climate Change by Florida State hurricane scientist James Elsner and the deputy director of the National Typhoon Center in South Korea, Namyoung Kang. The researchers found that this extra heat energy has led to a change in both the frequency and intensity of global tropical storms and hurricanes. Using a new mathematical framework to categorize all global tropical cyclones with wind speeds of at least 39 mph over the past 30 years, the authors showed that the observed warming of Earth's oceans during that time period has led to an average increase in wind speed of about 3 mph (1.3 m/s) for each storm--but there were 6.1 fewer named storms globally each year because of the warmer oceans. A typical year has about 85 named storms globally, so this represents about a 7% decrease in the number of storms.

Figure 1. One of the most spectacular images ever captured of a tropical cyclone from space: Category 5 Super Typhoon Maysak as seen from the International Space Station at approximately 6 pm EDT Tuesday March 31, 2015 (just after dawn local time.) At the time, Mayask had top winds of 160 mph as estimated by the Joint Typhoon Warning Center, and a central pressure of 905 mb, as estimated by the Japan Meteorological Agency. Image has been brightened and flipped 180 degrees. Image credit: Terry W. Virts.

Why fewer storms, but the strongest ones getting stronger?
More moisture is evaporated from a warmer ocean surface, resulting in water vapor concentrating in the lower atmosphere. Since moist air is less dense than dry air, this creates greater instability, leading to stronger updrafts in developing storms and more intense tropical storms and hurricanes. However, this low-level moisture is not effectively transported to high altitudes, resulting in warmer and drier conditions aloft and stronger high pressure in the middle and the upper troposphere. This high pressure aloft forces thunderstorm activity to concentrate in time and space, resulting in fewer tropical cyclones--but the increased moisture at low levels allows more efficient intensification once a tropical storm is spawned. "Thus tropical cyclone intensity increases at the expense of tropical cyclone frequency", the authors wrote. In an interview at, Kang said, "In a warmer year, stronger but fewer tropical cyclones are likely to occur. In a colder year, on the other hand, weaker but more tropical cyclones." Many climate models also predict fewer but more intense tropical cyclones in a future warmer climate--for example, Knutson, T. R. et al., 2010, "Tropical cyclones and climate change", which projected intensity increases of 2 - 11% by 2100. The "official word" on climate, the 2013 IPCC report, predicts that there is a greater than 50% chance (more likely than not) that we will see a human-caused increase in intense hurricanes by 2100 in some regions. The 2014 U.S. National Climate Assessment found that "the intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s. The relative contributions of human and natural causes to these increases are still uncertain. Hurricane-associated storm intensity and rainfall rates are projected to increase as the climate continues to warm.”

While it is good news that warming of the oceans may potentially lead to fewer hurricanes, this will probably not decrease the total amount of hurricane damage if the strongest storms get stronger. Damage done by a hurricane increases by somewhere between the second and third power of the wind speed, so just a 10 mph increase in winds can cause a major escalation in damage. According to Pielke et al., 2008, over the past century, Category 3 - 5 hurricanes accounted for 85% of U.S. hurricane damage, despite representing only 24% of U.S. landfalling storms. Category 4 and 5 hurricanes made up only 6% of all U.S. landfalls, but accounted for 48% of all U.S. damage (if normalized to account for increases in U.S. population and wealth.) This study also found that hurricane damages in the U.S. were doubling every ten years without the effect of climate change, due to the increases in wealth and population. If we add in an increase in the frequency of the strongest storms, combined with storm surges that will be riding inland on top of ever-increasing sea levels due to global warming, the damage math for coastal regions gets very impressive for the coming decades.

Nam-Young Kang, James B. Elsner, "Trade-off between intensity and frequency of global tropical cyclones", Nature Climate Change, 2015; DOI: 10.1038/nclimate2646

Pielke, R.A, et al., 2008, "Normalized Hurricane Damage in the United States: 1900 - 2005," Natural Hazards Review, DOI:10.1061/ASCE1527-6988(2008)9:1(29)

Hurricanes and Climate Change: Huge Dangers, Huge Unknowns, my 2013 blog post

The Atlantic remains quiet
High wind shear and dry, sinking air continue to dominate the tropical Atlantic, and none of the reliable models for predicting tropical storm formation show a tropical depression or tropical storm forming over the next five days. However, the models are showing that the remains of an old cold front extending from Florida's Gulf Coast to the waters offshore of North Carolina could serve as the focus of the development of a low pressure area capable of transforming into a tropical storm, early next week. Anything that does form along this front would move northeastwards, out into the open Atlantic, and not be a significant threat to any land areas.

Jeff Masters
About the Blogs
These blogs are a compilation of Dr. Jeff Masters,
Dr. Ricky Rood, and Angela Fritz on the topic of climate change, including science, events, politics and policy, and opinion.