Rising temperatures across the U.S. have reduced lake ice, sea ice, glaciers, and seasonal snow cover over the last several decades. Jump to “Arctic Sea Ice and Lake Ice is Melting”
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Culture, Climate Science & Education
What You Need to Know About Principle 8: Climate change will have consequences for the Earth system and human lives
The impacts of climate change on humans and the environment has become a focus for tribal, state, and federal governments, resource managers, medical professionals, emergency managers, insurance companies, military planners, and just about everybody else concerned about a livable, sustainable future.
Poverty, a lack of resources, and the absence of political will compound existing problems. Many feel that the challenge of the 21st century will be in preparing communities to adapt to climate change while reducing human impacts on the climate system (known as mitigation). Many jobs, if not entire industries, will emerge to address these complex issues. Indeed, our response to climate change presents tremendous opportunities for young people to make good money while making the world a better place to live.
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Southeast and Caribbean Region Impacts
Mean Global Temperatures are Increasing
The main impact of climate change is predicted to be an increase in global mean temperature over most land surfaces. We have already seen major changes. The table at left below lists the sixteen warmest years from 1880 to 2015. Note that all have occurred in the last 17 years. The animated chart at right below shows a rainbow-colored record of global temperatures spinning outward from the late 19th century to the present as the Earth heats up. Read more…
The New Normal
Temperature Increases Across the U.S.
What are our Possible Temperature Futures?
The Consequences: What We Can Expect
Increase of Less than 2 °C
Arctic sea icecap disappears, leaving polar bears homeless and changing the Earth's energy balance dramatically as reflective ice is replaced during summer months by darker sea surface. Now expected by 2030 or even earlier.
Tropical coral reefs suffer severe and repeated bleaching episodes due to hotter ocean waters, killing off most coral and delivering a hammer blow to marine biodiversity.
Droughts spread through the sub-tropics, accompanied by heatwaves and intense wildfires. Worst-hit are the Mediterranean, the south-west United States, southern Africa and Australia.
2 °C to 3 °C
Summer heatwaves such as that in Europe in 2003, which killed 30,000 people, become annual events. Extreme heat sees temperatures reaching the low 40s Celsius in southern England.
Amazon rainforest crosses a "tipping point" where extreme heat and lower rainfall makes the forest unviable - much of it burns and is replaced by desert and savannah.
Dissolved CO2 turns the oceans increasingly acidic, destroying remaining coral reefs and wiping out many species of plankton which are the basis of the marine food chain. Several metres of sea level rise is now inevitable as the Greenland ice sheet disappears.
3 °C to 4 °C
Glacier and snow-melt in the world's mountain chains depletes freshwater flows to downstream cities and agricultural land. Most affected are California, Peru, Pakistan and China. Global food production is under threat as key breadbaskets in Europe, Asia and the United States suffer drought, and heatwaves outstrip the tolerance of crops.
The Gulf Stream current declines significantly. Cooling in Europe is unlikely due to global warming, but oceanic changes alter weather patterns and lead to higher than average sea level rise in the eastern US and UK.
4 °C to 5 °C
Another tipping point sees massive amounts of methane - a potent greenhouse gas - released by melting Siberian permafrost, further boosting global warming. Much human habitation in southern Europe, north Africa, the Middle East and other sub-tropical areas is rendered unviable due to excessive heat and drought. The focus of civilisation moves towards the poles, where temperatures remain cool enough for crops, and rainfall - albeit with severe floods - persists. All sea ice is gone from both poles; mountain glaciers are gone from the Andes, Alps and Rockies.
5 °C to 6 °C
Global average temperatures are now hotter than for 50m years. The Arctic region sees temperatures rise much higher than average - up to 20C - meaning the entire Arctic is now ice-free all year round. Most of the topics, sub-tropics and even lower mid-latitudes are too hot to be inhabitable. Sea level rise is now sufficiently rapid that coastal cities across the world are largely abandoned.
6 °C and Above
Danger of "runaway warming", perhaps spurred by release of oceanic methane hydrates. Could the surface of the Earth become like Venus, entirely uninhabitable? Most sea life is dead. Human refuges now confined entirely to highland areas and the polar regions. Human population is drastically reduced. Perhaps 90% of species become extinct, rivalling the worst mass extinctions in the Earth's 4.5 billion-year history.
Heating Up: A Dangerous Spiral
This graphic, drawn up by Ed Hawkins, a climate scientist at the University of Reading in the United Kingdom, features a record of global temperatures spinning outward from the late 19th century to the present as the Earth heats up. The graphic displays monthly global temperature data, specifically how each month compares to the average for the same period from 1850-1900. At first, the years vacillate inward and outward, showing that a clear warming signal had yet to emerge from the natural fluctuations that happen from year to year. But clear warming trends are present in the early and late 20th century.
Can you determine about what year temperatures really started to rise?
So, the Earth's average temperature has increased about 1 degree Fahrenheit during the 20th century. What's the big deal?
One degree may sound like a small amount, but it's an unusual event in our planet's recent history. Small changes in temperature correspond to enormous changes in the environment. For example, at the end of the last ice age, when the Northeast United States was covered by more than 3,000 feet of ice, average temperatures were only 5 to 9 degrees cooler than today.
Now look at the spiral below, which shows simulated global temperature change from 1850 up to 2100 relative to the 1850 - 1900 average (how old will you be in the year 2100?). The temperature data are from Community Climate System (CCSM4) global climate model maintained by the National Center for Atmospheric Research. The simulation is for the IPCC Representative Concentration Pathway 8.5 (RCP8.5) emission scenario. RCP8.5 is the most aggressive scenario in which green house gases continue to rise unchecked through the end of the century, leading to an equivalent of about 1370 ppm CO2, which is roughly four times the concentration at present.
The Sixteen Hottest Years on Record
The chart above shows the global combined land and ocean temperature rank and how much the average temperature for that year departed from the average temperature for the period from 1880 to 2015. Note that of the 16 hottest years on record for that period have occurred in the last 17 years. The prediction of NASA and international climate scientists is for the trend to continue and even accelerate. For example, eighty years from now, the mean global temperature is expected to be 7 to 11 °F warmer than it is today.
Arctic Sea and Lake Ice is Melting
Rising temperatures across the U.S. have reduced lake ice, sea ice, glaciers, and seasonal snow cover over the last few decades. Mount Rainier’s glaciers are an example. The mountain's glaciers are the largest single-mountain glacier system in the contiguous 48 states. They represent 25% of the total ice area in the contiguous 48 states and contain as much ice (by volume) as all the other Cascade volcanoes combined. However, these glaciers shrank 22% by area and 25% by volume between 1913 and 1994 due to global warming. In the Great Lakes, total winter ice coverage has decreased by 63% since the early 1970s. This includes the entire period since satellite data became available. When the record is extended back to 1963 using pre-satellite data, the overall trend is less negative because the Great Lakes region experienced several extremely cold winters in the 1970s. Read more…
Source: National Climate Assessment
Use the slider bar on the image to compare the extension of older sea ice in the Arctic in September 1984 and September 2016 (note: it may take a moment for the slider to appear).
Credit: NASA Earth Observatory
The Arctic is a Seriously Weird Place Right Now
- Published: November 21st, 2016
- Source: http://www.climatecentral.org/news/arctic-sea-ice-record-low-20903
By Brian Kahn
The sun set on the North Pole more than a month ago, not to rise again until spring. Usually that serves as a cue for sea ice to spread its frozen tentacles across the Arctic Ocean. But in the depths of the polar night, a strange thing started to happen in mid-October. Sea ice growth slowed to a crawl and even started shrinking for a bit.
Intense warmth in both the air and oceans is driving the mini-meltdown at a time when Arctic sea ice should be rapidly growing. This follows last winter, when temperatures saw a huge December spike.
Sea ice extent using JAXA satellite measurements. Credit: Zack Labe
Even in an age where climate change is making outliers — lowest maximum sea ice extent set two years in a row, the hottest year on record set three years in a row, global coral bleaching entering a third year — the norm, what’s happening in the Arctic right now stands out for just how outlandish it is.
“I’ve never seen anything like it this last year and half,” Mark Serreze, director of the National Snow and Ice Data Center, said.
The latest twist in the Arctic sea ice saga began in mid-October. Temperatures stayed stuck in their September range, pausing sea ice growth. By the end of the month, the Arctic was missing a chunk of ice the size of the eastern U.S.
|RELATED||Warm Temps Slow Arctic Sea Ice Growth to a Crawl|
The oddness continued into November. A large area of the Arctic saw temperatures as much as 36°F above normal, further slowing Arctic sea ice growth and even turning it around for a few days. In other words, it was so warm in the Arctic that despite the lack of sunlight, sea ice actually disappeared.
“ The ridiculously warm temperatures in the Arctic during October and November this year are off the charts over our 68 years of measurements,” Jennifer Francis, a climate scientist at Rutgers University who studies the Arctic, said.
Compounding the warm air is warm water. Sea surface temperatures on the edge of the ice are also running well above normal in many places, further inhibiting sea ice growth.
As a footnote, Antarctic sea ice is also record low, making for a really dire global sea ice graph. The two regions’ current conundrums aren’t connected, and researchers are still trying to untangle what’s happening there. But in the Arctic, a number of factors — both driven by climate change and weather patterns — are to blame for this year’s bizarre sea ice situation.
Global sea ice extent is also at a record low. Credit: Wipneus
First, Arctic sea ice itself has some issues. Old ice has all but disappeared since record keeping began in the 1980s, and the majority of the ice pack is now young ice that tends to be more brittle and prone to breakup when extreme warmth strikes.
Some of that warmth came courtesy of the tropics where convection patterns created a series of large troughs and ridges in the atmosphere. The pattern that set up in mid-October put the eastern edge of one of these troughs over northeast Asia, according to Paul Roundy, an atmospheric scientist at the University of Albany.
Drag split-screen slider or click on before/after link.
A comparison of the extension of older sea ice in the Arctic in September 1984 and September 2016.
Credit: NASA Earth Observatory
“The result has been a strong surface low that has funneled warm air at the surface across the Bering Strait,” he said. “A similar low set up in the wave train over the North Atlantic, providing another pathway for warmth into the Arctic.”
The ocean heat has roots in this summer, when dark open water absorbed the sun’s incoming energy (compared to white sea ice, which reflects it back into space). Francis said this “not only slowed the freezing process, but also warmed and moistened the air. That extra moisture is very important because water vapor is a greenhouse gas and it also tends to create more clouds — both of these effects help trap heat near the surface.” It’s what Serreze said was a “double whammy” of warming causing the current meltdown.
This all follows what was the second-lowest sea ice extent ever recorded in September and what has been a persistent dwindling of Arctic sea ice for decades on end as climate change cranks up the heat.
The Arctic is warming twice as fast as the rest of the planet and it’s possible that the region could see ice-free summers as early as the 2030s. If carbon pollution continues at its current pace, it would likely make ice-free summers the norm by mid-century.
Going forward, Serreze said research should focus as on how an already changing Arctic system responds to these types of shocks.
“A valuable way of viewing Arctic system now is (looking at) how it responds to these extremes. Has their impact changed now that Arctic has changed?” he said.
Arctic Oceans, Sea Ice, and Coasts
The impacts of reduced sea ice include severe and coastal erosion, isolation for rural villages and reduced habitat for wildlife
The Arctic Ocean is blanketed by seasonal sea ice that expands during the frigid Arctic winter, reaching a maximum average extent each March. Sea ice retreats during the Northern Hemisphere's summer, reaching its minimum extent for the year every September. Arctic ice cover plays an important role in maintaining Earth’s temperature—the shiny white ice reflects light and the net heat that the ocean would otherwise absorb, keeping the Northern Hemisphere cool.
Arctic sea ice extent in September 2012 was the lowest in the satellite record (since 1979). The magenta line indicates the September average ice extent from 1981 to 2010.
Arctic sea ice is declining at an increasing rate in all months of the year, with a stronger decline in summer months. Researchers who study climate and sea ice expect that, at some point, the Arctic Ocean will lose virtually all of its late summer ice cover. A robust range of evidence suggests that Arctic sea ice is declining due to climate warming related to the increased abundance of heat-trapping (greenhouse) gases in the atmosphere from human burning of coal, oil, and gas. Because greenhouse gases stay in the atmosphere for multiple decades, scientists do not expect any reversal in the downward trend in ice extent.
Despite year-to-year variations, satellite data show a decline of more than 13 percent per decade in September ice extent since the satellite record began in 1979. The satellite data are less comprehensive before 1979, but shipping records and other evidence show that the ice extent has been in a continued state of decline for at least the last one hundred years. Climate models have long predicted that summer sea ice would disappear as temperatures rose in the Arctic, but ice loss has occurred even faster than any models predicted. Researchers now expect that the Arctic Ocean will be virtually ice-free in summer well before the end of this century, perhaps as early as the 2030s.
Impacts of reduced sea ice
Arctic amplification refers to the magnified warming in the Arctic relative to the rest of the globe—the rate of warming in the Arctic is nearly two times the global average. While a number of mechanisms contribute to Arctic amplification, the loss of Arctic sea ice cover plays a dominant role due to the reduction in the net albedo—a measure of how well a surface reflects incoming solar energy.
In 2012, the Parry Channel—a portion of the long-sought Northwest Passage—went from ice-choked on July 17 (left) to open water on August 3 (right). Sea ice reflects most of the sunlight energy that hits it back into space; open water can absorb heat energy from the sun.
White or light-colored sea ice is very reflective, so its albedo is higher than that of ocean water. With the huge increase in the area of ice-free water compared to a decade ago, the ocean can absorb much more heat than it used to. This, in turn, means that more heat energy is available to be released back into the atmosphere in autumn as sunlight wanes. As ice cover shrinks, areas of open water absorb heat that the ice would have reflected. The water warms up, and before ice can form again in the fall the ocean must release some of that heat to the atmosphere. Scientists are concerned that this increased heat transfer to the atmosphere could magnify future climate warming trends.
Sea Level is Rising and Coasts are Eroding
Melting of ice sheets and glaciers, combined with the thermal expansion of seawater as the oceans warm, is causing sea level to rise. There is strong evidence that global sea level is now rising at an increased rate and will continue to rise during this century.
While studies show that sea levels changed little from AD 0 until 1900, sea levels began to climb in the 20th century.
The two major causes of global sea-level rise are thermal expansion caused by the warming of the oceans (since water expands as it warms) and the loss of land-based ice (such as glaciers and polar ice caps) due to increased melting. Read more…
Click the button below for a summary of how sea level rise will affect coast of the Southeast
For a good summary of climate change impacts on global sea level rise, visit the National Climate Assessment
The Southeast Coastline: Savannah, Georgia
See how rising sea levels will affect Georgia's coast under different global warming conditions. Be patient, the visualization tool can take a few minutes to load, depending on your internet connection.
Be sure to scroll down in the window below to learn more.
Sea level is on the rise. Since 1900, it's gone up an average of eight inches around the world, due to global warming. And by 2100, it will be higher still — maybe as high as six-and-a-half feet above 1992 levels. That would put the homes of 7.8 million Americans at risk of being flooded.
Sea level rise: Global warming's yardstick
By Rosalie Murphy,
NASA's Jet Propulsion Laboratory
One of the Argo array’s buoys begins collecting ocean temperature data after a science team deploys it in the Atlantic Ocean. Credit: Argo / University of California, San Diego.
Global sea levels have been ticking steadily higher by about an eighth of an inch (3.2 millimeters) each year since scientists began measuring them two decades ago. That’s why Carmen Boening, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, was so shocked in 2010 and 2011, when she saw a quarter-inch (five-millimeter) drop in sea level – a sudden reversal of the trend.
“We knew that either the sea was cooling, or there was less water in the ocean,” Boening said. Like metal, water contracts when it cools. “So we used NASA’s GRACE mission, which basically weighs water to tell us how much is present in different parts of the world, both in the ocean and on land. We found there was actually less water in the ocean.”
Water can’t just vanish. If it leaves the ocean, it has to show up somewhere else in the water cycle. Sure enough, Boening’s team found huge amounts of precipitation and flooding in Australia and South America. GRACE data suggested lots of water had evaporated from the ocean during the 2011 La Niña event. Then other wind patterns pushed the precipitation to Australia.
“It had to be a combination of all these events at once, and that’s why the drop was so large,” Boening said. “But at some point, it had to run off into the ocean. That’s what happened next.” A few months later, the ocean returned to the previous year’s levels and the upward trend resumed.
How NASA measures sea level
Global sea levels have risen by about 8 inches in the last 130 years. It might not sound like much – but the ocean covers about 70 percent of Earth’s surface and holds about 99 percent of its water. A tiny rise or fall involves a lot of water.
“Sea level rise is the yardstick for global warming,” said Josh Willis, a research scientist at JPL. “It’s the ruler by which we measure how much human activity has changed the climate. It’s the sum of the extra heat the ocean has absorbed and the water that’s melted off of glaciers and ice sheets.”
The Ocean Surface Topography Mission (OSTM)/Jason-2 measures sea surface height. Credit: NASA
Willis leads NASA’s Jason missions, satellites that measure sea level and ocean surface topography, or variations in ocean surface height at different areas around the globe. This variation is driven in part by deeper currents and weather patterns like El Niño, La Niña and the Pacific Decadal Oscillation. These patterns move huge amounts of water from some regions of the ocean to others, pushing some parts of the surface downward and others upward.
The GRACE twin satellites make detailed measurements of Earth's gravity field. Credit: NASA
The Gravity Recovery and Climate Experiment (GRACE) mission, which helped Boening and Willis track water during the 2011 La Niña, collects data using twin satellites orbiting Earth together. When the lead satellite encounters a slight change in Earth’s gravity, the force pulls it a little further from its partner. The second satellite measures the distance between them to estimate the strength of Earth’s gravity.
The planet’s gravity changes because different amounts of mass have piled up at different places. There’s a lot more Earth in the Himalaya, for example, than in the Mississippi Delta. Similarly, when water coalesces in a certain part of the ocean, it tugs on GRACE’s satellites a little harder.
But changes on land also play a role. For example, Greenland’s ice is melting. "As the land loses mass, its gravitational pull is not as strong, so it’s losing its ability to attract water,” Boening said. Though melting land ice from Greenland and glaciers account for about two-thirds of sea level rise to date, “sea level around Greenland is actually going down.”
Mass, height and heat
The ocean is also gaining heat. Small heat transfers happen constantly at the ocean’s surface and, eventually, the ocean swallows most of the heat greenhouse gases have trapped in Earth’s atmosphere. That heat warms the whole ocean, causing it to expand.
Expansion seems simple, but measuring it is a challenge. “Over 90 percent of the heat trapped inside Earth’s atmosphere by global warming is going into the oceans,” Willis said. Temperature data from 19th-century ship, compared to a set of 3,600 buoys measuring ocean temperature today, confirms that the ocean – especially its upper half – has warmed since 1870.
In the bottom half of the ocean, though, it’s harder to tell. Buoys measure only about halfway to the bottom, a depth of about 1.25 miles (2,000 meters). Over many decades, ocean currents pull water from the surface of the ocean toward its depths. Scientists have assumed the deep ocean has been warming, too – but a new paper by Willis and other JPL scientists found no detectable warming below that 1.25-mile (2,000-meter) mark since 2005.
“We can’t see heat in the deep ocean yet. The effect has been too small over our ten years of data, and the ways the ocean can get heat down deep are very slow. It might take a hundred years,” Willis said. “We still have to rely on the data and not our simulations to figure out what’s going on in the deep ocean. So we have some more scientific work to do.”
On the other hand, another paper from the same journal found that earlier studies drastically underestimated warming in the Southern Ocean, since the 1970s. New estimates suggest it absorbed anywhere from 25 to 58 percent more heat than previous researchers thought.
Scientists will continue learning more about the ocean’s intricacies, correcting assumptions and revising old estimates. But Willis warns against losing sight of the strong global trend toward rising sea levels.
“The picture is very simple,” he said. “The ocean heats up and causes sea level rise. Ice melts and causes sea level rise. We can see the results at the shoreline.”
This feature is part of a series exploring how NASA monitors Earth’s water cycle. Other ocean missions include Aquarius, which measures the ocean’s salinity to offer scientists clues about evaporation and rainfall patterns and changes in the ocean’s density, which can drive circulation patterns. The Surface Water and Ocean Topography (SWOT) mission will improve topography measurements at the coast after its 2020 launch. Learn more about all of NASA’s Earth science missions.
Changing precipitation and temperature are altering the distribution and availability of water
Climate plays an important role in the global distribution of freshwater resources. Changing precipitation patterns and temperature conditions will alter the distribution and availability of freshwater resources, reducing reliable access to water for many people and their crops. Read more…
Good summaries of impacts on freshwater can be found in the National Climate Assessment
High Streamflow is Increasing, Raising Flood Risks
Extreme Weather Events are Increasing
Incidents of extreme weather are projected to increase as a result of climate change—indeed they already have increased and are projected to increase much more. Many locations will see a substantial increase in the number of heat waves they experience per year and a decrease in episodes of severe cold. Precipitation events are expected to become less frequent but more intense in many areas, and droughts will be more frequent and severe in areas where average precipitation is projected to decrease. Explore the graphics on this page to see how things have already changed.
Move through the slides below to see how weather is becoming more extreme through the seasons in the continental U.S.
Risk of Extreme Weather From Climate Change to Rise Over Next Century, Report Says
By SABRINA TAVERNISEJUNE 22, 2015
Drought in Puerto Rico has left the La Plata reservoir nearly empty. A study in The Lancet predicts a growing number of people will be affected by extreme weather over the next century.
WASHINGTON — More people will be exposed to floods, droughts, heat waves and other extreme weather associated with climate change over the next century than previously thought, according to a new report in the British medical journal The Lancet.
The report, published online Monday, analyzes the health effects of recent episodes of severe weather that scientists have linked to climate change. It provides estimates of the number of people who are likely to experience the effects of climate change in coming decades, based on projections of population and demographic changes.
The report estimates that the exposure of people to extreme rainfall will more than quadruple and the exposure of people to drought will triple compared to the 1990s. In the same time span, the exposure of the older people to heat waves is expected to go up by a factor of 12, according to Peter Cox, one of the authors, who is a professor of climate-system dynamics at the University of Exeter in Britain.
Climate projections typically are expressed as averages over large areas, including vast expanses, like oceans, where people do not live. The report calculates the risk to people by overlaying areas of the highest risk for climate events with expected human population increases. It also takes into account aging populations — for example, heat waves pose a greater health risk to old people.
Men in Pakistan cool themselves in a river near Islamabad during a heatwave. The Lancet study is part of an effort to look at how climate might change life on earth for people.
Aamir Qureshi/Agence France-Presse — Getty Images
The report is part of a series of efforts to analyze how climate change might affect human health. Other major climate reports, the Intergovernmental Panel on Climate Change, a global document, and the National Climate Assessment in the United States, have addressed the issue. But Professor Cox said the new report was the first large-scale effort to quantify the effects that different types of extreme weather would have on people.
“We are saying, let’s look at climate change from the perspective of what people are going to experience, rather than as averages across the globe,” he said. “We have to move away from thinking of this as a problem in atmospheric physics. It is a problem for people.”
The Lancet first convened scientists on the topic in 2009, and produced a report that declared climate change was “the biggest global health threat of the 21st century.” Monday’s report notes that global carbon emission rates have risen above the worst-case scenarios used in 2009, and that in the absence of any major international agreement on cutting those rates, projections of mortality and illness and other effects, like famine, have worsened.
“Everything that was predicted in 2009 is already happening,” said Nick Watts, a public health expert at the Institute for Global Health at University College London, who led the team of more than 40 scientists from Europe, Africa and China that produced the report. “Now we need to take a further step forward. The science has substantially moved on.”
For years, climate change was presented in terms of natural habitats and the environment, but more recently, experts have been looking at how it might change life on earth for people. Scientists and some governments are trying to frame the dangers of climate change in health terms in order to persuade people that the topic is urgent, not simply a distant matter for scientists. Governments around the world are preparing for a United Nations summit meeting on climate change in Paris in December to discuss new policies to limit greenhouse-gas emissions.
The report measures the increase over time in “exposure events,” which it defines as the number of times people experience any given extreme weather event.
By the end of the century, the report estimates, the exposure to heat waves each year for older people around the world is expected to be around 3 billion more cases than in 1990. The number of times people of all ages are exposed to drought would increase by more than a billion a year. The rise in exposures to extreme rain would be around 2 billion a year by the end of the century, in part because populations are growing.
Even without climate change, the health problems that come along with economic development are significant, the authors note. About 1.2 million people died from illnesses related to air pollution in China in 2010, the report said.
Most broad climate reports do not go further than explaining the science, but much of the Lancet report is dedicated to policy prescriptions to slow or stop climate change and mute its effects on health. It notes that using fewer fossil fuels “is no longer primarily a technical or economic question — it is now a political one,” and urges governments to enact changes that would accomplish that.
Oceans are becoming more acidic
The chemistry of ocean water is changed by absorption of carbon dioxide from the atmosphere. Increasing carbon dioxide levels in the atmosphere is causing ocean water to become more acidic, threatening the survival of shell-building marine species and the entire food web of which they are a part.
The oceans are not, in fact, acidic, but slightly basic. Acidity is measured using the pH scale, where 7.0 is defined as neutral, with higher levels called "basic" and lower levels called "acidic". Historical global mean seawater values are approximately 8.16 on this scale, making them slightly basic. To put this in perspective, pure water has a pH of 7.0 (neutral), whereas household bleach has a pH of 12 (highly basic) and battery acid has a pH of zero (highly acidic). Read More…
For a good summary of climate change impacts on ocean acidification, visit the National Climate Assessment:
Click on the image to enlarge
It's Not Just Acidification that's Harming the Oceans: Two Other Major Effects of Climate Change on the Earth's Oceans
Oceans are heating up too. Learn how ocean temperatures have changed over the past century:
Climate change may be choking the ocean’s oxygen supply too. Learn about the results of an indepth study of dissolved oxygen in the Earth's oceans since 1958.
Ecosystems are changing
Ecosystems on land and in the ocean have been and will continue to be disturbed by climate change. Animals, plants, bacteria, and viruses will migrate to new areas with favorable climate conditions. Infectious diseases and certain species will be able to invade areas that they did not previously inhabit.
In recent years, millions of pinyon pine trees in the American Southwest have died due to drought and high heat. Global climate models predict persistent drought for the American Southwest under current rates of change. They also project changes of similar magnitude to many other ecosystems across the western US and across the globe.
Learn about some of the ecosystem changes occurring in the Northeast by clicking on the topics below
For a good summaries of climate change impacts on tribes, the Northeast, and aquatic ecosystems in the Rockies, explore these publications:
Climate change is altering the timing of natural events
Timing matters: Flowers bloom, insects emerge, birds migrate, and planting and hunting seasons are carefully coordinated times in order to take advantage of what other organisms, or the weather, is up to.
But increasing research is showing some of these relationships are falling out of sync as climate change alters important cues, such as the arrival of spring warmth.
"There are going to be winners and losers," said David Inouye, a biology professor at the University of Maryland, Read more…
For a good summary of impacts on seasonal patterns of plants and animals, visit the National Climate Assessment:
For a brief account of how climate change is affecting hummingbirds and their nectar sources, read this article from Audubon:
Are Early Blooms Putting Hummingbirds At Risk?
Audubon’s chief scientist talks migration, climate change, and what you can do to help.
Published Apr 07, 2015
No one understands the relationship between climate change and hummingbirds better than Audubon’s chief scientist Gary Langham. He led a groundbreaking study in 2014 that determined that about half of all North American bird species will lose their homes if we don’t do something to stop global warming. Now, to further that study, Audubon is sourcing data from people across the country who host hummingbirds in their backyards. The project, called Hummingbirds at Home, starts up again on April 8.
Langham emphasized the importance of Hummingbirds at Home to Audubon while answering questions about what will happen to the 18 or so hummingbird species in the United States (including rare visitors from Mexico) and the role citizen scientists play in ensuring their survival.
What were some of the regular challenges of a hummingbird migration even before climate change became a factor?
Well, any kind of migration, let alone a hummingbird, is sort of a minor miracle. Imagine a Ruby-throated Hummingbird crossing the Gulf of Mexico in one flight. How in the world does it have enough energy stored up in that little body? It’s just amazing. And then you factor in all of the threats it has to encounter, from weather to manmade structures.
So how has climate change made it worse?
If the nectar sources you depend on bloom too early, you run the risk of showing up after the party’s already over. That’s one of the things that got us thinking about Hummingbirds at Home. The Broad-tailed Hummingbird’s primary food source right now is this big yellow flower called the glacier lily. There’s research out of the University of Maryland showing that the bird is still arriving at its breeding grounds in the Rockies at the same time as previous years, but that climate change is causing the glacier lily to open up earlier and earlier in the season. It’s not hard to extrapolate that soon, Broad-tailed Hummingbirds may show up and not have their main food source. Maybe new flowers will take the glacier lily’s place. Or maybe this shift will turn out to be really bad for the bird.
Are some hummingbirds more endangered by climate change than others?
The hummingbird I grew up with in California, the Anna’s Hummingbird, was mercifully on the climate stable list (in the Audubon Birds and Climate Change Report). But unfortunately, one of the other coastal California hummingbirds, the Allen’s, is listed as climate-endangered. Its summer range seems to be decreasing, whereas the winter range is shifting northward pretty dramatically. The Rufous is also listed as climate-endangered. In some ways, it might be affected even more dramatically than the Allen’s. The other two species listed as climate-threatened are the Calliope and Black-chinned Hummingbirds.
So the Broad-tailed isn’t one of them?
While the Broad-tailed Hummingbird, in the way we did the climate report, was shown to be stable, its food sources are not. The food sources and a lot of ancillary things that are really important to animals are actually not included in our report. And that makes the prospects even more dire than what we projected.
How will Hummingbirds at Home help these species?
If we can better understand what the hummingbirds are feeding on, we can maybe get ahead of the curb and plant things that are either climate-stable or that will properly match up with the birds’ migrations. To me, the next iteration is to generate a specific list of plants that people can use for hummingbirds in their areas.
In the three years since Hummingbirds at Home started, what has stood out to you about the project?
People are very passionate about their backyards and gardens, and they’re very passionate about hummingbirds. Hummingbirds are like raptors. They somehow have this supernatural ability to capture people’s attention. Because hummingbirds come in people’s yards, they’re also a great way to engage kids. One of the things that’s kind of lost in our digital world is that connection to nature.
Is the eventual goal to have something as long-running and as scientifically useful as, say, the Breeding Bird Survey or the Christmas Bird Count?
I think that would be great! I hesitate to forecast anything for an individual project, but I could imagine that it would do just that. Or maybe we’ll broaden it to be more inclusive of a broader range of birds, or maybe it will be absorbed by something else. We want whatever it is we’re doing to feel meaningful to people and be fun and free and family-friendly.
Human Health and Mortality will be Affected
Human health and mortality rates will be affected to different degrees in specific regions of the world as a result of climate change. Although cold-related deaths are predicted to decrease, other risks are predicted to rise. The incidence and geographical range of climate-sensitive infectious diseases—such as malaria, dengue fever, and tick-borne diseases—will increase. Drought-reduced crop yields, degraded air and water quality, and increased hazards in coastal and low-lying areas will contribute to unhealthy conditions, particularly for the most vulnerable populations.
The wide range of climate-related challenges facing every community are enormous and may appear at times to be overwhelming. The U.S. and other militaries around the world recognize climate change as a serious, potentially catastrophic national and global security threat. Read More…
Climate Change and Health Issues for Tribes
For good summaries of climate change impacts on human health, click the buttons below
Around the World: Climate change affects human communities. So does the mining of fossil fuels, which cause climate change. For information on those impacts, visit these sites:
What Difference Does Half a Degree in Warming Make?
What's the difference between a two-degree world and a 1.5-degree world? The Paris climate conference in 2015 pledged not just to keep warming “well below 2 °C,” but also to "pursue efforts" to limit warming to 1.5 °C.
But how much of a difference can half a degree Celsius make? First, let's do the conversion to °F since that's the units used in the U.S.: 2 °C = 3.6°F and 1.5 °C = 2.7 °F.
So in degrees Fahrenheit, we're talking about a difference of less than 1°F (.9 °F to be exact). That doesn't sound like much of a difference. But adding half a degree of heat to the world's climate system turns out to make an enormous difference. Here's what the science says:
A Summary of Impacts
Listen to how climate change is affecting the traditional food of Southeast tribes
Click the button below to learn what the National Climate Assessment says about the Southeast
Misconceptions about this Principle
Global warming will be good for humans
The misconception or myth goes something like this: “…Two thousand years of published human histories say that warm periods were good for people. It was the harsh, unstable Dark Ages and Little Ice Age that brought bigger storms, untimely frost, widespread famine and plagues of disease.”
Scientist predict climate change will bring many more costs than benefits.
The science says: climate change will have many more costs than benefits. While it is expected that global warming may bring a few benefits in the short term, it is expected that over the longer term, it will bring few or no benefits to human society and instead will do great harm at considerable cost. Learn more…