Figure 1: The Amazon rainforest to reach irreversible tipping point. Image: Al’fred / Shutterstock.com
Loading the atmosphere with five million tonnes of CO2 every hour has pushed the Earth dangerously close to a no-return threshold, beyond which lies an inhabitable hothouse world. There are 15 known tipping points in the planet's complex climate system, and nine of them-including permafrost, the Amazon rainforest, the Greenland ice sheet, Arctic sea ice, and the Atlantic Ocean's circulation - are drifting alarmingly, as reported in the journal Nature. The authors of this journal persist that it is an existential threat to civilization, implying that the Earth is in a state of planetary emergency.
Tipping points are reached when particular impacts of global heating become unstoppable, such as the runaway loss of ice sheets or forests. In the past, extreme heating of 5 degC was thought necessary to pass tipping points, but the latest evidence suggests that this could happen between 1 degC and 2 degC.The planet has already heated by 1 degC and the temperature is expected to rise further, due to past emissions and increasing greenhouse gases. The authors further warned that one tipping point, such as the release of methane from thawing permafrost, may fuel others, leading to a cascade. However, the researchers who wrote in a commentary article in the journal Nature acknowledged that the complex science of tipping points means great uncertainty remains. But they say the potential damage from the tipping points is so big and the time to act so short, that to misapprehend this situation is not a responsible option. They call for urgent international action.
Prof Tim Lenton at the University of Exeter, the lead author of the article, said that the threshold for a cascade of interrelated tipping points has already been crossed. Phil Williamson at the University of East Anglia, who did not contribute to the article, also agreed on the prognosis made by Tim Lenton and his colleagues and said that we might have already lost control of the Earth’s climate. This new article comes as the United Nation warns action is very far from stopping global temperature rise, with the world currently on track for 3-4 degC. The commentary lists nine tipping points that may have been activated as shown in Figure 2.
Figure 2: Schematic diagram illustrating nine tipping points that may have been activated.
All signals indicate that part of the west Antarctic ice sheet may be in irreversible retreat as well as the Wilkes basin in east Antarctica. The collapse of these ice sheets would eventually raise sea level by many meters. The massive Greenland ice sheet was melting at an accelerating rate while the Arctic sea ice is shrinking fast. Alarming evidence indicates that the Permafrost across the Arctic is beginning to irreversibly thaw and release carbon dioxide and methane. According to a few studies, the Gulf Stream current in the Atlantic which brings heat to Europe has also slowed down by 15% since the mid-20th century. The scientists report that 17% of the Amazon rainforest has been lost since 1970 and the tipping point, where loss of forest leads to it drying out, could lie in the range 20%-40%. In temperate forests, especially in North America, heating has triggered more fires and pest outbreaks, potentially turning some regions from a sink for carbon to a source. In the tropics, corals are predicted to be wiped out by an increase in sea surface temperature of 2 degC.
A cascade of tipping points could occur because the melting of Arctic sea ice amplifies heating by exposing dark ocean that absorbs more sunlight. That may increase the melting of Greenland ice and permafrost areas. Multiple risks can interact, with one change reinforcing another, and therefore, warming of just a degree or two is sufficient to result in dramatic cascading effects. Prof Martin Siegert, at Imperial College London, said: “The new work is valuable. They are being a little speculative, but maybe you need to be.” He also pointed out that the extremely rapid rate at which CO2 was being pumped into the atmosphere was unlikely to have ever occurred on Earth before. “It may mean that tipping points can occur in unexpected ways as there is no geological precedent for this rate of CO2 change.”
The article reports that preliminary results from the latest climate models suggest global heating will be greater than expected, increasing the risk of tipping points. Prof Piers Forster, at the University of Leeds, disagreed on that point. However, he added: “I completely endorse their call for action. Although possibly low probability, the risks they identify are real.” Lenton said action would still have real benefits, by slowing the impacts and giving more time for people to adapt. He said: “This article is not meant to be a counsel of despair. If we want to avoid the worst of these bad climate tipping points, we need to activate some positive social and economic tipping points [such as renewable energy] towards what should ultimately be a happier, flourishing, sustainable future for the generations to come.”
Look, up in the sky! It’s a Bunny, it’s a heart, it’s a UFO! No, it’s Global Cloud Climatology! (Photo Credit: International Satellite Cloud Climatology Project)
On average, the global cloud amount is approximately 65-72% (counting cirrus). - International Satellite Cloud Climatology Project
There’s more to cloud climatology than picking out what animal it most closely resembles. We can define a cloud as a visible region consisting of suspended particles of ice, liquid, or a combination of both. To form a cloud, we must increase the relative humidity such that it is greater than 100%. This can be done through radiative cooling or increasing the mixing ratio (i.e. the amount of the water vapor). There are 10 main cloud types formed from cirrus, stratus, and cumulus type clouds. Cloud climatology consists of defining clouds in terms of cloud amount, heights, cloud top temperature, optical depth, distribution, radiance, and lifecycle. Not all clouds precipitate either. (Precipitation is also intimately linked with global cloud climatology. Precipitation is typically associated with areas of rising air and low atmospheric pressure. The atmosphere itself is dramatically affected by latent heating associated with precipitation, an ultimate driver in overall precipitation patterns. Temperatures changes within the atmosphere also play a large role in the development and dissipation of clouds. Aerosols can act as cloud condensation nuclei, accelerating the rain process or inhibiting it).
The average cloud amount varies seasonally and with time of day, driven by solar radiation. Over land, cumulus tend to form in the early morning with dissipation in the early afternoon due to mixing. Cumulonimbus tend to take over in the late afternoon and evening hours in the continental summer, due to more organized forcing. The tropics have the highest total low cloud amount, while the total cloud amount is highest in the Northern Hemisphere winter associated with the midlatitude storm track. It is thought that high clouds could have an impact on warming and low clouds a net cooling effect, but these processes aren’t fully understood or use indirect observational evidence of low clouds. And yet, the Cloud-Radiative Forcing (CRF) experiment found that a climate system without clouds would have a net warming effect.
Ground-based cloud observations have been largely subjective in determining cloud type and somewhat sparse over the ocean. Detecting clouds through satellite data often involves techniques, such as cloud masking to identify the presence of clouds through comparison of the brightness temperature of pixels (i.e. cold pixels will be clouds). Over polar regions, the cooler brightness temperatures of snow and ice-covered surfaces may possibly be mistaken for clouds. Although 3% uncertainty exists with cloud amount in climatology, ground-based stations and satellite comparison should be able to minimize potential sources of error in cloud climatology and help to better understand the role clouds play in a changing climate.
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©2019 Meteorologist Sharon Sullivan
As temperatures begin to plummet, you may be wondering – where the heck is global warming? Well, unfortunately, it’s still around.
First off, remember the difference between the terms “global warming” and “climate change”. “Global warming” was initially used by scientists because it describes how greenhouse gases trap heat in the atmosphere and warm the planet’s overall temperature. However, this temperature increase is one symptom of climate change – which includes melting land ice, changes in seasons, and sea level rise, among other things. Ultimately, climate change can be described as a shift towards extremes. Hurricanes become stronger, heavy rains become heavier, droughts last longer, heat waves are more intense, and cold snaps are also more severe. In the case of winter weather, snowstorms become stronger, dump more snow, and bring more cold. This shift towards extremes means more record-challenging snowfalls and cold temperatures this winter, and in winters to come.
Additionally, temperatures in the Arctic are warming, which causes shifts in the jet stream, an atmospheric pattern that is responsible for much of the weather in the United States. Warmer temperatures in the Arctic push the jet stream farther south, which brings frigid Arctic air further south and lingers there longer. This allows winter storms not only to be more severe, but to last longer as the jet stream’s swings tend to stay in place for a while. The jet stream could also slow, as it depends on temperature differences between the Arctic and tropical/equatorial regions. As the Arctic warms, the difference in temperature between these two regions becomes smaller, and because of this smaller difference, the jet stream will slow down. This is sometimes referred to as “atmospheric stagnation”, and it means that weather systems stay in place longer since they aren’t being carried away by the jet stream. So, a strong winter storm that stays in one area will continue to bring snow, wind, and cold weather until it finally gets carried away by the slower jet stream.
Fortunately, there are things you can do this winter to help mitigate the effects of climate change. Try keeping your house a little bit colder and not cranking up the heat too high. You can always put a sweatshirt, blanket, or a nice pair of fuzzy socks on to keep you warm, and the energy saved by this action will not only help the planet, but your wallet as well.
©2019 Meteorologist Margaret Orr
DISCUSSION: The Hawaiian island chain has shattered dozens of records regarding various temperatures since the late-Spring and extending into early Fall. Of note are ocean temperatures which, as recent as August 2019, had indicated temperatures as much as 3 degrees Fahrenheit higher than normal. This warmer than average oceanic temperature is expected to exacerbate coral bleaching, which appeared heavily in as recent as 2015.
Coral bleaching has been known to be a direct result of warm ocean temperatures, however not all events are due to this factor. According to the National Oceanic and Atmospheric Administration (NOAA), “when water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white.” Often during a coral bleaching event the coral is not dead, but is subject to intense strain and are thus susceptible to mortality. The state Division of Aquatic Resources (DAR) recently identified, areas of bleaching at Molokini and along the south shore from Makena to Maalaea. Certain species of coral in Molokini have already shown to be at or near 50% bleached.
If temperatures return to normal quickly, the likelihood of coral survival is increased, as it experiences decreased stress. Arizona State University Center for Global Discovery and Conservation Science (GDCS) has partnered with NOAA and DAR on coral reef science, conservation and management in Hawaii, offering programs such as the Pacific Ridge-to-Reef Initiative providing conservation and management practices that are bioculturally sustainable to ensure flourishing reefs in the future, by utilizing advanced aircraft satellite monitoring and modeling of reefs throughout Hawaii.
For more information on sea surface temperatures or coral bleaching events, visit the Global Weather and Climate Center!
© 2019 Meteorologist Jessica Olsen
There are already signs that the weakening of the Atlantic circulation is having an effect on U.S. fisheries and storms. Ice melting off Greenland as the Arctic warms is believed to play a key role. Credit: NASA
A key question for climate scientists in recent years has been whether the Atlantic Ocean's main circulation system is slowing down, a development that could have dramatic consequences for Europe and other parts of the Atlantic rim. But a new study suggests help may be on the way from an unexpected source -- the Indian Ocean. Think of it as ocean-to-ocean altruism in the age of climate change.
The new study, from Shineng Hu of the Scripps Institution of Oceanography at the University of California-San Diego and Alexey Fedorov of Yale University, appeared recently in the journal Nature Climate Change. It is the latest in a growing body of research that explores how global warming may alter global climate components such as the Atlantic meridional overturning circulation (AMOC). AMOC is one of the planet's largest water circulation systems. It operates like a liquid escalator, delivering warm water to the North Atlantic via an upper limb and sending colder water south via a deeper limb. Although AMOC has been stable for thousands of years, data from the past 15 years, as well as computer model projections, have given some scientists cause for concern. AMOC has showed signs of slowing during that period, but whether it is a result of global warming or only a short-term anomaly related to natural ocean variability is not known and the issue of AMOC stability should not be ignored. The mere possibility that the AMOC could collapse should be a strong reason for concern in an era when human activity is forcing significant changes to the Earth's systems. The last time AMOC weakened substantially was 15,000 to 17,000 years ago, and it had global impacts, like harsh winters in Europe, with more storms or a drier Sahel in Africa due to the downward shift of the tropical rain belt.
Much of Fedorov and Hu's work focuses on specific climate mechanisms and features that may be shifting due to global warming. Using a combination of observational data and sophisticated computer modeling, they plot out what effects such shifts might have over time. For example, Fedorov has looked previously at the role melting Arctic sea ice might have on AMOC. For the new study, they looked at warming in the Indian Ocean. Warming of the Indian Ocean is considered one of the most robust aspects of global warming. The researchers said their modeling indicates a series of cascading effects that stretch from the Indian Ocean all way over to the Atlantic: As the Indian Ocean warms faster and faster, it generates additional precipitation. This, in turn, draws more air from other parts of the world, including the Atlantic, to the Indian Ocean. With so much precipitation in the Indian Ocean, there will be less precipitation in the Atlantic Ocean, the researchers said. Less precipitation will lead to higher salinity in the waters of the tropical portion of the Atlantic -- because there won't be as much rainwater to dilute it. This saltier water in the Atlantic, as it comes north via AMOC, will get cold much quicker than usual and sink faster. "This would act as a jump-start for AMOC, intensifying the circulation," Fedorov said. On the other hand, how long this enhanced Indian Ocean warming will continue is unknown. If other tropical oceans' warming, especially the Pacific, catches up with the Indian Ocean, the advantage for AMOC will stop.
The researchers said this latest finding illustrates the intricate, interconnected nature of global climate. As scientists try to understand the unfolding effects of climate change, they must attempt to identify all of the climate variables and mechanisms that are likely to play a role, they added. There are undoubtedly many other connections that are unknown.
1. Shineng Hu, Alexey V. Fedorov. Indian Ocean warming can strengthen the Atlantic meridional overturning circulation. Nature Climate Change, 2019; DOI: 10.1038/s41558-019-0566-x
Climate change has had extreme impacts in India. Rise in average global temperatures have led to a worrying trend of no rain for long periods and then a sudden bout of excessive rainfall, causing extreme weather events, particularly floods which took lives, destroyed homes and agricultural yields as well as resulted in huge revenue losses. The resulting floods are being exacerbated by unplanned urban growth and environmental degradation, driving millions from their homes and causing widespread damage.
For centuries, Indians have rejoiced at the arrival of the monsoon to break summer’s fever. This year, India’s monsoon season has overrun by almost a month, with unprecedented rainfall causing deaths from collapsing buildings and many crops beginning to rot. Normally the monsoon in north India recedes by the beginning of September, but the average rainfall this month has been 37% above normal. If the situation continues for the remaining few days, it will be the latest the monsoon has ever receded in decades, according to experts in the India Meteorological Department.
The torrential rains that submerged parts of India this year are the latest in a string of major floods in the past decade, some caused by record rainfall - a scenario that many fears could become the “new normal” as climate change increases the frequency of extreme weather. This year, the monsoon arrived late with fierce intensity, where spells of heavy rain have led to flooding in 11 states, taking 1200 lives and displacing millions. India’s summer monsoon has always been variable and has often precipitated floods, especially in the basins of the great Himalayan rivers. But experts say that a combination of global warming, unplanned urban growth, and environmental degradation is increasing flood risk in India.
New studies show that extreme precipitation events are on the rise in large parts of India, especially multi-day deluges that lead to large-scale floods. Warmer temperatures are also speeding up glacier melt in the Himalayas, which is projected to increase flow rates in the Ganges and Brahmaputra Rivers. Last year’s historical floods in the southern state of Kerala were due to the destruction of mountains and hills, as well as development on floodplains and marshes which are exacerbating risks. These floods were caused by extreme rainfall and mismanagement of dam reservoirs, but mining and construction in the Western Ghats, a major hill range, contributed to damaging landslides. The floods in August 2018 took 483 lives, affecting 5.4 million people, and temporarily shut down the state’s new airport, which was built on a floodplain.
One key to preventing or reducing flood damage is understating the shifting contours of the summer monsoon, which brings about 35 inches of rainfall to India every summer. A complex weather system influenced by both global atmospheric circulation and regional meteorological forces, the monsoon is an important piece of the climate puzzle- any change in the system affects the food and water security of billions in the Indian subcontinent, many of them extremely poor.
To view other interesting weather-related phenomenon visit the Global Weather and Climate Center!
© 2019 Oceanographer Daneeja Mawren
Discussion: Astronomical Fall has officially started and with that is a good time to reminisce back on how summer 2019 shaped up! NOAA’s National Center for Environmental Prediction has released their report of climate statistics for this past summer (June 2019-August 2019). The average summer temperature across the contiguous United States was 72.4°F which was 1.0°F above normal and the average minimum temperature was 59.9°F. The minimum temperatures ranked in the upper third of the climate record (1985-2019), coming in 1.5°F above normal since the records were first taken in 1895. The above normal temperature trend occurred in states across the northeastern United States, on the West coast, and in the South. According to NOAA, this summer as a whole rank in the upper third of the climate record. All of the states all experienced near or above average temperatures this summer. No states were below normal. Alaska’s average temperature this summer was 54.6°F, 4.1°F above normal, which marks this summer as the second warmest since 1895. Anchorage, Alaska experienced its warmest summer. The average temperature was 63.2°F. This temperature was 1.8°F higher than the summer of 2004.
The average total of summertime precipitation this year was 8.83 inches, which was above average by 0.51 inches. Since the records began in 1895, this summer also ranked in the top third of the climate record for wettest summer. From the northern Great Plains to the East Coast, many states experienced above average precipitation. States in parts of the Ohio Valley and the Mid-Atlantic region saw much above average precipitation. The opposite could be noted for parts of the western and southern United States. Those regions experienced a summer of below average precipitation. The standout state was Arizona, which experienced its driest summer on record. Other western and southwestern states such as California, New Mexico and Utah all had their tenth driest or lower summer. Utqiagvik, Alaska broke a thirty-year precipitation record. This summer they received 5.43 inches of precipitation breaking the old record of 5.24 inches set in 1989! Now that summer 2019 is in the books, it will be interesting to see how fall shapes up climatologically across the United States.
To check out more climate statistics and interesting facts be sure to click on the following link: https://www.ncdc.noaa.gov/sotc/national/201908
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© 2019 Meteorologist Shannon Scully
For days now the world has been watching as the Amazon suffers a major blow thanks to a record number of wildfires that have scorched huge swaths of the rainforest. These fires started back in August 13th, 2019, and have since been reported all across the South American continent, affecting all sectors of the Amazon, including those areas of the rainforest that neighbor Brazil. And as outrage from both the public and world leaders continues to be echoed all across both social media platforms and protests in cities around the world, questions have been raised regarding to why these fires occurred at the intensity and sheer size that they did and whether or not the biome will be at greater risk for these sorts of extreme fire seasons in the near-future.
Fires that have been reported in the Amazon from August 13th to August 26th of 2019. Source: Business Insider
Fires are nothing new to the Amazon Basin; the area experiences natural wildfires every year owing to recurring phenomena such as dry spells and lightning strikes. Unfortunately, the region has experienced a sharp increase in annual wildfire episodes not only due to climate change but also due to man-made ones. Deforestation is nothing new and has been rampant in the region for decades as private investors, cattle ranchers, and loggers all converge over large areas of the rainforest and continually remove acres of land on a daily basis by means that include everything from chopping down trees to starting legal (and illegal) forest fires. Indeed, the loose government regulations owing to Brazil’s current administration along with dry spells over the basin have exasperated this year’s number of wildfires to levels that surpass those seen in 2016 and most of this decade.
The fires have indeed gotten so out of control over the Amazon Basin that their sheer size and magnitude are even visible from space, as satellite imagery has suggested. As such, smoke has plagued nearly the entire country of Brazil, with its largest city, Sao Paulo, experiencing intensive cloud cover and dark skies as a result.
Clear skies over the central Amazon basin in July 2019 juxtaposed with much hazier/smoky conditions over the exact same area the following month. Source: CNN/NOAA
Dark skies in the middle of the day over Sao Paulo, Brazil, on August 19th, 2019. Source: Business Insider
Outrage over these wildfires has been noted at the local and national level in Brazil as environmental activists have called out President Bolsonaro and his administration for loosening regulations that would otherwise defend more of the Amazon Rainforest by protesting on the streets of several major Brazilian cities including Sao Paulo. Many protesters and activists have also argued that the current administration has essentially been downplaying most of what has been occurring over the last few weeks, resulting in Bolsonaro suggesting that it’s actually the environmentalists that have started several of the recent wildfires(https://www.businessinsider.com/amazon-rainforest-photos-before-after-wildfires-2019-8#environmental-activists-have-been-fighting-to-save-the-rainforest-for-years-here-a-greenpeace-protest-calls-deforestation-a-crime-near-the-brazilian-town-of-claudia-mato-gross-in-2005-23). As for global reactions to the situation, world activists including Leonardo DiCaprio and Shakira have commented on the events that are unfolding in the Amazon and have donated to help fight the wildfires. Moreover, world leaders recently held a G7 Summit in which they have promised to also donate money and provide emergency services to Brazil.
As the rest of the world looks on at what’s currently taking place in the Amazon, many have started to ask how they and their communities can help to preserve the rainforest. Several accredited organizations are out there and have been included in this article. For more information on how you can donate to services committed to help with this crisis,visit:https://www.refinery29.com/en-us/2019/08/241249/amazon-rainforest-fires-how-to-help-donate-organizations
©2019 Meteorologist Gerardo Diaz Jr.
Volcanic Eruptions Can Reduce Global Average Temperature (Credit: UCAR and Meteorology Today by C. Ahrens)
Volcanic eruptions have the potential to change the global average temperature and have done so in the past. There are just two important factors that can make this happen. These eruptions have to be massive and the spewed contents need to have a significant amount of sulfur dioxide and ash. One evident example of this is what is famously known as “The year without a summer”.
The year 1816 was notoriously known for its cold and gloomy summer, where overcast skies and rain was frequent. In order to explain the cold summer event, scientists researched global climatic changes and events over the past year. It was discovered that this massive eruption became the main cause of 1816’s chilly summer. On April 5th, 1815, Mt. Tambora in Indonesia erupted. The build up, however, took a staggering four months as ash and dust spewed high into the atmosphere, blocking out the sun. Based on its duration and magnitude, this eruption was dubbed the largest in recorded history. As the ash spewed into the air, debris that didn’t fall back to the ground was picked up by the trade winds and circulated around the world; a process that takes months. By the time the summer of 1816 came around, the global average temperature had decreased by about three degrees Celsius.
The small particles of ash from the eruption travel around the globe becoming perfect condensation nuclei for water vapor. Condensation nuclei is a term to explain how the particles of ash act as an object the water vapor in the air can easily attach to. The process of collision continues to grow the piece of ash into a water droplet. This occurs when more droplets of water continue to attach to the particle by colliding into it as it gets pushed around by the movement of air. Eventually, all the ash in the air will collect into a bigger droplet of vapor and form a cloud. With more ash in the air, this process increases cloud cover in the atmosphere and leads to increased precipitation. Clouds are notorious for blocking out the sun. In the case of the year 1816, this is exactly what happened. Most of the summer was cloudy and rainy.
Sulfur Dioxide, a gas released during volcanic eruptions, also combines with water vapor in the atmosphere. When this happens the chemicals react and the droplets of water vapor become droplets of sulfuric acid. Sulfuric acid is a great sunlight reflector. Naturally in our atmosphere, Sulfuric Acid is known as a coolant, contributing to the cooling of the earth's surface. With an increased amount of Sulfuric Acid in the atmosphere, the more likely it is to increase the cooling process. With the 1815 eruption, Mt. Tambora caused a significant amount of Sulfuric Acid to form. It takes about three years for Sulfuric Acid to collect into rain droplets and rain out of the atmosphere. So, with the highest content of sulfuric acid in the atmosphere the following year along with the increased cloud cover from the microparticles, the global average temperature decreased.
Another example of volcanic eruption that changed global average temperature occurred in 1991. Mt. Pinatubo in the Philippines spewed an estimated 20 million tons of Sulfur Dioxide into the atmosphere. Model predictions were in agreement that the global average temperature had dropped by 0.5 degrees Celsius and the following two years recorded below average temperatures around the world. This eruption was not nearly as big as the eruption of Mt. Tambora. However, it was still a large eruption that had a significant effect on the global average temperature.
It is very interesting how much one large eruption has an effect on our atmosphere. The effect made by Mt. Tambora was certainly the largest in recorded history. Although uncertain and difficult to predict, it is possible that another eruption could occur at some point in the future which may also have an effect on the global average temperature. There are still plenty of active volcanoes to this day that record seismic activity and/or spew lava and ash on occasion. Even after blowing its top in 1815, Mt. Tambora is one of the few/many volcanoes still active to this day.
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© 2019 Meteorologist Alexandria Maynard