A major weather pattern shift will be occur next week for North America into the Arctic as the jet stream…which already has been largely higher in amplitude and experiencing some blocking with little eastward progression of long-waves in the upper-atmosphere, will becoming extremely amplified (north-south) next week bringing very warm air up into Alaska, Yukon and the Arctic Ocean and a modified Arctic air mass from Nunavut and the Northwest Territories of Canada into the central US. Let’s take a look at things.
The current pattern dominating North America has been strong ridge of high pressure over the Western US or Eastern Pacific with a prominent trough over the eastern US with some fluctuation in the wave pattern east or west, but not much significant change, except in the center of the country which has seen more significant swings between these two states. The east, including even the Southeast saw significant snow. The west has seen abnormal warmth with record fires in California. Currently the ridge of upper-atmosphere ridge is forecast by US and European models to build to an extremely high amplitude the end of next week north over portions of Alaska and Yukon and into the margins of the Arctic Ocean. This as a very intense trough is forced south over the US.
This extreme amplification will drive an Arctic surface air high pressure system out of the Northwest Territories with very cold air this week, with this air mass advancing into the US beginning Thursday into this weekend. Meanwhile stormier conditions will moving from the Bering Sea into the Chukchi Sea driving up temperatures in the far north. And California with all the fires? Remains abnormally warm and dry.
As I spoke about in a previous post, the Arctic is having its second warmest year on record and lowest annual sea ice volume on record as climate change continues to abnormally warm the Arctic. The highly amplified wave pattern is much a product of the current weak La Nina pattern. However, the intensity of the amplification and resulting amplified warming of the Arctic is also a function of the long-term global warming regime dominating the polar region and causing record warmth and reductions in sea ice. I noticed this amplified wave pattern will have interesting impacts on the Arctic weather pattern and possibly the tenuous sea ice beginning next week.
Right now, a prominent surface high pressure region…associated with the Beaufort Gyre…is over the Arctic Ocean north of Alaska and eastern Siberia. By the middle of next week, this gyre will weaken as strong low pressure systems approach the Arctic from both the Bering Sea and the far North Atlantic.
The Gyre is vulnerable because of the areas of open water and tenuous sea ice which remains over the Chukchi Sea…record low extent for this time of year. The ice being cold creates the surface high pressure system and clockwise circulation. But last year, this gyre collapsed because of slow sea ice growth allowing for storms with warm, moist air to move into the Arctic and further slowed sea ice growth. It appears this may be forecast to happen again during the tail end of this month.
Depending on the strength of the low pressure systems, not only will the tenuous sea ice in the Arctic…widespread areas 1.5 meters or less in thickness (less than a meter in the Chukchi Sea)…deal with more warm air temperatures limiting sea ice growth, but also wave action which may destroy the ice, particularly from the Pacific side as cyclones are expected to move across the Arctic from the Pacific. We’ll see how much impact those storms have and how intense they are. If the upper-level wave pattern is as amplified as forecast by models 5-8 days out (no reason to think otherwise as he reach the point of good reliability for the upper-atmosphere), it’s a good set up for strong low pressure systems to develop in both the North Pacific and North Atlantic. And with the highly amplified blocking high over the Eastern Pacific, storms will be forced to track into Alaska and into the Chukchi and Beaufort Seas and deep Arctic Ocean.
–Meteorologist Nick Humphrey
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Today, NOAA presented the State of the Arctic report at the American Geophysical Union annual conference in New Orleans. The news from the report was devastating for potential weather and climate impacts. Lots of important info to talk about from this! Let’s summarize:
Annual Arctic sea ice extent is the lowest in 1600 years. This is based on proxy data (tree rings, lake sediments, ice cores from the Greenland Ice Sheet). There has been an abrupt decrease in extent during the 20th century (continuing to present).
Arctic sea ice extent reached a record minimum in the warm season in 2012. However, 2015-17 witnessed consecutive record low maximum extents in the cold season. 2016 also had the lowest extent on record in November or December. 2017 is also witnessing top two or three low daily extents in November into December, with record low sea ice in the northern Bering Sea and the Chukchi Sea (north of the Bering Strait between Alaska and Russia). Also very notable, sea ice VOLUME (which includes thickness of ice) has continued to suffer with 2015-17 in the top 4 for the lowest volume on record going back to 1979 (and based on decreasing of sea ice extent and thickness, likely much much longer than that). Multi-year ice…ice more than a year old…is now nearly extinct in the Arctic Ocean.
The Arctic had its warmest year on record in 2016 and its second warmest year on record in 2017 in reliable records. The climate of the Arctic is warming to the point that permafrost is increasingly melting releasing methane and carbon dioxide, methane emissions from what are called methane hydrates (methane gas locked in water ice) are increasing from the very shallow continental shelves surrounding the Arctic Ocean and mid-latitude weather patterns are becoming altered because of reduced sea ice (more on this shortly). The Arctic tundra is also greening at an increasing rate because of rapid warming.
NOAA specifically states that “the Arctic shows no signs of returning to a reliably frozen region of recent decades” because of continued climate change related warming.
Discussion – Leaving the Ice Age Era:
One thing that we must remember about the sea ice of the Arctic Ocean (and the Southern Ocean around Antarctica) is that sea ice is a product of Ice Age eras. Our planet has had a tendency historically to flip between two global climate equilibrium states with dramatically different regional weather and seasonal patterns. The Ice Ages and the Hot House “Jurrasic Park” climates have been the two long-term dominating climate regimes in Earth’s history. One characterized by huge ice sheets and low sea levels, the other characterized by no ice sheets, no sea ice and high sea levels. Human civilization has flourished in the latest interglacial period in the Ice Age era because the climate has remained largely stable for roughly 10,000 years (-1 to +0.5 degrees C relative to mid-20th century climate) and mild enough to for extensive agriculture and settlements.
But now, because of Anthropogenic Global Warming (AGW) from climate change, we are leaving that stability in the geologic blink of an eye.
Probably the most important regulars of climate during Interglacials are the “refrigerators” of the north and south…the Arctic Ocean sea ice and Antarctic Ice Sheet (also Greenland Ice Sheet). However, as temperatures warm because of human carbon dioxide emissions trapping heat in the global climate system, that heat warms the atmosphere and ocean, attacking the sea ice by providing excess latent heat of melting. For the Arctic, this reduces the sea ice extent and volume decade after decade. Eventually, it will get to a point, where sea ice will become so thin and tenuous, it will undergo collapse to what has been called a “blue ocean” event with 1,000,000 sq km or less ice at a minimum in September (2012 extent minimum record was 3.41 million sq km). The 2016 and 2017 extent minimums were in the top 10 with 4.14 and 4.64 million sq km, 2nd and 8th respectively. 8 of the top 10 warm season minimum extents (in km) have occurred since 2010 in the now 39 year record. The Arctic Ocean and lower atmosphere are warming and becoming more like the high latitude North Atlantic. Eventually sea ice is expected to disappear completely in the warm season in the Arctic. Some climate scientists have suggested over the past several years that the “blue ocean” event resulting from a collapse of sea ice extent could occur between 2015-2020 or so as multi-year ice has nearly gone extinct, leaving thin ice vulnerable to quick melting and battering waves from cyclones. Computer models have been terrible at dealing with the end of sea ice in the Arctic, suggesting it would stick around into the second half of this century.
Discussion – Weather and Climate Implications:
So why does loss of sea ice matter? Sea ice regulates the climate of the world in multiple ways. It acts as large white surface which reflects most of the shortwave solar radiation from the sun (high albedo). As a result, it keeps the Arctic and Northern Hemisphere (and world) cooler than otherwise. It’s wide physical presence means heat entering the Arctic Ocean goes into melting the ice in the warm season (latent heat of melting; heat goes into phase change of water from solid to liquid) instead of heating the ocean and atmosphere dramatically (sensible heat to change temperature). Losing sea ice ends its presence as a climate regulator, allowing for more abrupt warming of the atmosphere-ocean system and increasing moisture content in the atmosphere (water vapor is an additional greenhouse gas; and increased clouds may reflect some radiation, but also can limit cooling in darkness). In addition, the Arctic Ocean will warm as it is a dark surface (low albedo). Increasing ocean warming in the marginal seas of the Arctic Ocean is already leading to increased methane emissions from the shallow continental shelves (as subsea permafrost thaw the clathrates) and more rapid warming will lead to an increase in emissions of methane and carbon dioxide from land permafrost (see discussion by Arctic climate scientist Dr. Peter Wadhams of Cambridge University on YouTube). Methane is over 100 times more powerful greenhouse gas than carbon dioxide on a timescale of several years (it dissipates far faster in the atmosphere, but sudden releases can increase warming quickly). And all of these feedbacks will much more quickly destroy the sea ice extent through further warming for a longer period in the warm season until ice disappears completely.
Increased warming of the Arctic also has impacts on mid-latitude weather. There has been research suggesting that the jet stream can be strongly influenced by Arctic warming and sea ice extent (see discussion by Dr. Jennifer Francis on YouTube). This can include a weakening of the upper-level jet stream which depends on the temperature difference between the upper-level mid-latitudes and polar atmosphere (known in meteorology as “baroclinic instability”). This weakening can lead to the jet stream developing high-amplitude waves more frequently, allowing for powerful upper-level ridges of high pressure to develop and cause blocking of the progressive westerly flow. This blocking can cause more frequent stagnant weather for locations, developing droughts in some areas through prolonged dryness, long periods of heavy precipitation in other regions as well as places of very abnormally warm temps (greater extreme summer heat) vs. colder temperatures (but the warmth always significantly outpaces the cold). Increased warming of the atmosphere in general also increases rainfall rates. In addition, paradoxically, while parts of the mid-latitudes may go through below normal temps and cold weather, the powerful ridging can produce extremely abnormally warm temperatures over the Arctic regions, intensifying the warming of the far north.
An identical pattern to this has largely set up over the Northern Hemisphere November into December.
The statistics of weather has already changed significantly because of global warming with far more extreme heat events, drought periods and heavy precipitation events than in the mid-20th century (see presentation by Dr. Aaron Thierry on shift to more extreme weather conditions; starts 12:30 min, recommend watching through 20:30 min; also see discussion of climate change on increasing extreme events by Dr. Stefan Rahmstorf). Going past tipping points far earlier than expected by climate models will increase the likelihood for far more extreme weather events as weather patterns and circulations change (in some cases difficult to predict ways). Clearly, the world still needs adequate mitigation and adaptation measures to deal with these rapid and possibly abrupt changes.
I may, perhaps, be providing a less popular view or one which isn’t the “flavor of the week”. But I’ve been hearing a lot of people recently in science discussing the communication of climate change. There has much criticism of how some have chosen to communicate. Examples: Statements considered “dire”; assuming moral or intellectual superiority if someone disagrees with the most sound parts of the science; being condescending, etc.
First off…I do agree with the idea that people need to treat people right and fair. Do not treat people like they are less than you or unnecessarily scare them into submission. We need to communicate what we know and how we understand it and listen to what people have to say.
But with that said…
The science of climate change (and it’s main mechanism…global warming) has been gaining scientific ground since the 1970s. The understanding of the greenhouse effect and carbon dioxide goes back to the mid-1800s. I was born in 1984. Climate scientist James Hansen went before Congress in 1988 to give the realities of what climate change means. The Intergovernmental Panel on Climate Change of the UN was formed in 1988. It’s 2017. The climate of Earth has warmed dramatically since then and as a result we are witnessing impacts on our world from more extreme meteorological and climatological events, extinction rates 1000 times higher because of humans with a possible mass extinction event underway in the biosphere and millions around the world and increasingly direct impacts on human health. Meanwhile too many deny what is happening because data isn’t enough. And in many cases, many of the people we are trying to convince are not only disinterested in learning, but have a sharp anti-intellectual bent based on politics or even religion. I have no problem with people being politically conservative or religious, but that is the reality of who most of the “deniers” are. So are we not supposed to call out people who are grossly thinking irrationally or being outright deniers (not skeptics, skeptics can be convinced) in order to protect their feelings and “hopefully” convince them we are correct? Climate scientists are routinely attacked by denier politicians and on social media and their reputations dragged through the mud. Hell, even threatened. Who speaks up for the integrity of the science and scientists while we all sit around trying to be nice and protect the feelings of people who are not interested in what we have to say, respectful or not?
I guess the reason I’m rather sharp about this is because I think Americans largely discuss this topic from a position of privilege. In America, climate change is still a joke for many or largely downplayed. “Look at all this snow, I guess they got 5 inches of global warming hahaha”. “I get climate change is an important issue, but do people really think it’s as important as [insert political issue here]”. And other various statements. I think there are two issues at work here.
In the US, we are dealing with the impacts of climate change, but we (generally) still have the resiliency to face what’s happening. In the developing world, this is not the case. There have already been significant increases in extreme events relative to the mid-20th century (droughts, fires, heavy precipitation leading to issues such as increased property destruction, even more importantly, crop failures putting more people at risk of undernourishment). And in some places, there’s sea level rise becoming a problem. In the developing world, this is not a game, or a joke or something to be denied. It’s in their face. Even if individual event/event types can’t be conclusively attributed to climate change, understanding climate change is a *systemic* process of our climate heat engine, adding more energy can cause more extremes across many categories. How much to developing nations realize these growing extremes? They’ve realized it enough to basically demand the industrialized nations who have caused a vast majority of the warming of Earth via 20th century emissions, to work to limit warming to as low as possible and pay for their mitigation measures. Unfortunately, they are largely ignored because their countries are small and not economically influential enough (Paris Agreement basically is business-as-usual lite), so the world is failing and they will suffer the worst impacts of global failure first.
Climate change is to outright deniers “something that’s always happening” or even to many of those who understand the basic science a more significant concern of the future. 2100 comes up a lot. Or perhaps “We have 10 years” which was since the late 1980s. How many times can we have 10 years to seriously discuss these problems? Climate change is happening now and changes *are* going to accelerate and be abrupt as we move forward. How can we discuss these issues if too many people think they know better than a PhD with 30 years of research experience? If the PhDer asserts in a blunt manner that they know better, we might think that’s intellectual superiority and unfair assumption as we all have different experiences beyond education. And technically that’s true…but if one is degrading someone because they are educated and they trust what they see over data, can we call it what it is? Anti-intellectualism and in some cases even moral superiority as it may be based on religion or politics is just as bad if not worse to our society than anything. This is clearly something anyone can be out of line on.
Us “intellectuals” seem to be having debates about how to best communicate climate change. We should talk about the worse case scenarios, should be have lots of hope and solutions, this and that. My view? Tell the truth! How can we do anything about climate change if people do not actually have an appreciation of what we are facing in terms of how it can directly harm human society and our biosphere? I’ve noted that even many outside of climate science do not fully appreciate what is happening now and how bad it could be. The “worse-case” is not…it is the path we are on in all of its unpleasantness unless we make the necessary changes needed. Every time I hear “stop being alarmist” I hear “don’t tell the truth”. It’s not being alarmist to discuss alarming things. This used to be an issue in meteorology. The US didn’t used to issue tornado warnings for fear of causing panic and freezing people up. Well, they didn’t know what was coming and were target practice for tornadoes smashing their towns. Yes, provide actionable info. “Go here to learn more”, “Vote for politicians who care about you and your children’s health and prosperity”…connect climate change’s shift to more extreme conditions to extremes which have already occurred and discuss how they will become normal as new extremes appear. “Yes we’ve always had droughts, but these droughts will come in more rapid succession, which is why we must have mitigation policies to prevent this from happening”. Tell people how these changes are already happening. Give people options how to act, but be real, otherwise, why should they be concerned about the issue? Especially when we as scientists get more bogged down about how everything supposedly gets attributed to climate change vs. simply providing a strong message about the seriousness of the situation, especially NOW, not just the future.
Respect goes both ways and if I’m going to respect the views of someone who doesn’t automatically agree with the science, I expect that person to respect my views and intelligence. Otherwise, I won’t trash that person, but I will move on. Some (and perhaps most) people are NOT looking to be convinced. And that’s something science communicators have to face. Not just trying to respectful, but also respecting yourself and not allowing lack of openness, compromise or cognitive dissonance stand in your way to providing knowledge. I’ve learned this from my experience as a meteorologist who are used as target practice all the time for supposedly being wrong 50% of the time (we are quite accurate), or anger over warnings (which have saved thousands of lives over decades). Climate change communicators should be respectful, be blunt, say things the way it is (consensus and personal scientific view), but not afraid to respectfully point out incorrect views and statements they KNOW are wrong and not afraid to move on if someone doesn’t want to listen. Most people will or will not figure it out on their own time, anyways.
Oh and more thing. If you don’t regularly even attempt to communicate climate change to people, don’t lecture others on how they should do it. I particularly don’t want to hear the “Now is not the time to talk about climate change” meme. I discuss these issues to people whenever I can and have encountered this criticism. If you have a problem with how its done, do it and do it better. It’s actually one of my motivations for creating this site. People who care about these issues care about the seriousness of it and the people and animals it is and will harm further. Trust me, communication is even more challenging than you believed and chances are you do not understand just how serious it is even if you think you do or even some of the latest science, which is evolving rapidly. The focus needs to be on helping the citizenry be educated on these issues so we have a healthy planet as well as defending our integrity from those who would diminish our importance in informing society.
–Meteorologist Nick Humphrey
(pictured at the top is a version of the famous “hockey stick” temperature curve by Mann 1999).
I found this discussion forum posted on YouTube with Dr. James Hansen and felt the need to share. Hansen is known as the “father of global warming awareness” since his testimony on the problem before Congress in the late 1980s and frequent contributions in both peer-reviewed literature and as a science communicator to the general public. This talk was posted just today from the latest international climate talks (Conference Of the Parties-23 or “COP-23” in Bonn, Germany) dealing with getting down details behind the Paris Climate Agreement signed the world’s nations in 2015 to try to limit global warming below 2 degrees C (3.6 degrees F) relative to 1750 and preferably below 1.5 C (2.7 F).
Here is the video (by user Nick Breeze who reports on Climate Change issues and interviews scientists…check out his YouTube Channel, good stuff)…audio isn’t the greatest but it is still highly recommended if you care about this important issue.
In this discussion, Hansen pretty much lays out a major problem. With all the talks over the years, nothing significant has been done to significantly reduce emissions of greenhouse gasses into Earth’s atmosphere. He points out something which other notable climate scientists have pointed out: We have run out of time as far as waiting on attempting to prevent “catastrophic warming” as far as impacts (those impacts really pick up intensity past 1.5 degrees C…we are currently around 1.1-1.2 C over the past few years) and while there are efforts to create alternative energy solutions and research carbon dioxide removal from the atmosphere, the only viable way he sees to get nations off of carbon is for govts to force the cost of fossil fuels to reflect the harm it causes to ecological and human health (pollution, climate change, etc). He’s spoken about how this could be done to put much of the money back in the pockets of Americans in the American political context (where the greatest monetary loss would likely be to the rich with a huge carbon footprint). But having the true ecological and human cost of fossil fuels…and not just the benefit in terms of driving the common economic drivers…be added to the cost would allow much greater competitiveness in the energy industry vs. now where fossil fuels are still by far the cheapest energy available for a variety of reasons (relative ease to extract, transport, existing technology vs. building new). And with oil companies influencing govts around the world, it makes it very hard to see realistic change outside of the pledges or changes which seem significant but in the end do little good on a global scale.
I made this blog partly for informing people about the realities of climate change as it is ultimately we who must make sound decisions and force our governments to do the same. These conferences and agreements are great (and obviously I disagree with President Trump’s position on the issue), but optics cannot be the only thing which comes out of all these COPs. We must have an evolutionary change in how we conduct business on our only habitable planet. There are means to turn the tide…but the political will (and money) have to be invested in actually doing it.
A weak La Nina atmosphere-ocean pattern has fully developed in the Pacific Ocean. This phenomenon is part of the cool phase of the El Nino Southern Oscillation (ENSO). It is characterized by abnormally low surface pressure in the Western side of the Pacific Basin and abnormally high pressure on the Eastern side. This causes an enhancement of the easterly trade winds, causing significant upwelling of cold water along the equatorial coast of South America, with a build up of very warm water in the Western Pacific.
ENSO patterns, as shown above can cause noticeable changes in the seasonal weather patterns over North America, particularly during the winter months. The jet stream can become more amplified, leading to a Pacific jet producing cooler and wetter than normal conditions over the Pacific Northwest, extending into the northern tier states. Meanwhile, the “Sun Belt” of the US can see abnormally warm, dry conditions.
The caveat of all this is is the strength of the La Nina versus the degree of influence other atmospheric patterns have on the seasonal climate variability. Other patterns include the North Atlantic Oscillation (NAO-surface pressure variability between the semi-permanent Icelandic Low and Azores High), Arctic Oscillation (AO-pressure anomalies between Arctic and mid-latitudes, closely related to NAO), and the Madden-Julian Oscillation (which can speed the development and enhance the effects of a El Nino or La Nina phase), among others on various timescales.
So what does it mean for our winter in the US? Well, as of now, the NWS Climate Prediction Center is generating winter temperature/precipitation forecasts accounting for the development of La Nina, with a strong latitudinal effect on temperature and precipitation. Below/above in the north and above/below in the south, respectively.
In the meantime, long-range forecasts show the North Atlantic Oscillation becoming “negative” later in November (characterized by a south to north pressure gradient between the Azores high over Portugal and the Icelandic to the north). This pattern is favorable for an amplified upper-level jet stream wave pattern over North America and the North Atlantic and intrusions of cold air deep into the eastern half of the US. So in the shorter term colder than normal conditions may be possible for these areas this month (as has already occurred this week).
When it comes to these “teleconnections”…the various cycles of variability within the annual climate regime of Earth…they can most definitely give us a head’s up on to what to expect in general. A canvas of how the weather may be behave over the course of days to weeks and months. But we must keep track of how these different cycles interact with each other and how they vary individually in terms of strength and mode. One curiosity is the strength and persistence of the La Nina. If it was fairly weak, it is more likely to be dominated by other teleconnections at times during the course of the winter, versus if it intensifies and produces more persistent effects on the upper-level air patterns.
Overall, the expected winter pattern is good news for drought-stricken areas in the northern tier such as Montana and the Dakotas. We will have to watch areas along the southern tier for potential further drought development. And as mentioned, November and at least early December could feature a more amplified jet stream so that even areas in the Southeast which may end up with an above average winter overall may see serious impacts from cold because of Arctic intrusions (something for citrus growers to watch out for in Florida, for example).
Fires have been raging across the world this year with unprecedented scope. Major wildfire outbreaks have been notable from tropical rainforests in Africa and South America to the taiga of Canada and Russia. Even Greenland has seen an unusual amount of fire activity on the edge of the ice sheet. This year, Western North America, and the Iberian Peninsula of Europe have been particularly hard hit with life-threatening fires (see HERE,HERE, and HERE). Although fires occur every year with variable impacts, a significant upward trend can be tied to climate change allowing both natural and human activity to ignite and expand the destructive intensity of wildfires.
Hello Weather & Climate News readers! This post will be the first (Part II) in what will be my ongoing education article series WxClimoEd. I hope to write educational posts on various topics related to weather and climate to help enhance your understanding of various phenomena and their impact on the environment, individuals and society. These posts will present key ideas and concepts and provide occasional linked sources to further, more detailed information.
Understanding Global Climate Change (Indicators)
In Part 2 of this article series on Global Climate Change, I’ll discuss the indicators of climate change in progress on Earth. Even without the global measurements of temperature, there are plenty of signs in the climate system that change toward a warmer world is in progress.
Earth Undergoing Abrupt Climate Change
While global warming is considered to be detectable since the First Industrial Revolution (after 1750), since the latter half of the 20th century, the environment has begun to exhibit what could be considered “abrupt” changes. Among scientists who study natural abrupt change in the paleoclimate records have had some common thought on what “abrupt” means: 1) Changes in climate which can be witnessed within a human lifetime and 2) the change is very nonlinear; it far exceeds the mechanism which initiated the change in the first place (See this video presentation by Dr. White at the American Geophysical Union Annual Meeting discussing past abrupt climate change in the paleoclimate record). In the past, abrupt change usually occurred as a result of the advance or recession of ice sheets, leading to rapid change in local temperature or regional circulations (or even global distributions of precipitation or temperature patterns). Today, abrupt change is being increasingly witnessed as a result of an already unnaturally fast mechanism (rapid rise in carbon dioxide concentration, resulting in rapid rise in global temperatures relative to natural variability…multi-decadal to centennial scales vs. multi-millennial).
Here are just some of the abrupt changes resulting from the changing climate happening now:
Decline in sea ice over the Arctic Ocean
2. Rapid increase in air temperature of the Arctic.
The Arctic (64-90N) has warmed around 3-4 degrees C since the 1881-1910 period (based on NASA data). 2-3 degrees C of warming has occurred just since the 1951-1980 period with notable warming since the year 2000. This has led to not only the rapid decline in Arctic sea ice, but the beginning the melting of land permafrost.
Addendum: The rise in the average temperature of Earth as a whole can count as abrupt, as seen in the earlier graph (farther back up). Most warming has occurred since the 1970s. The top ten warmest years on record going back to 1880 have occurred since 1998 (with 1998 now the last year in the top ten from the 20th century). 2017 is expected to be the 2nd warmest year on record just slightly behind 2016.
3. Increase in Sea Surface Temperatures and Oceanic Heat Content of Global Ocean.
The average sea-surface temperature of the global ocean from 60S-60N has risen around one degree C since the 1881-1910 period. 0.5 degrees C warming has occurred since 1980. Like the global air temperature, SSTs have been most of their record warm years since the turn of the 21st century, with an accelerated pace of warming since 2000 (1.62 degrees C/century currently, compared to 1 degree C/century 1950-2000). 2017 sea surface temperatures are currently running the 2nd warmest on record (NOAA data).
Earth’s seawater is slightly basic (basic is ph > 7). The global average ph of the oceans has decreased from 8.25 to 8.069 since the 1750s (ph was 8.104 in the 1990s). This is caused by the oceans dissolving carbon dioxide (30-40% of carbon dioxide released by humans dissolves in the oceans). This interaction forms carbonic acid, with further chemical reactions leading to increasing concentrations of the hydronium ion (H+). This leads to a lowering of the ph. The rate of acidifcation is faster than at anytime in the past 300 million years! The rapid acidification has been more pronounced in the Arctic Ocean because of very cold water (colder water can absorb more dissolved gases). When ph falls under 8 in the coming decades (assuming no mitigation), marine life which depend on carbonate structures (shellfish, sea snails, corals, some types of plankton, etc) begin to suffer from the corrosive effects of less basic waters.
The end of the 20th century into the early 21st century has featured a statistical increase in extreme weather events. Climatologists usually classify “extreme” as being 4-5+ standard deviations from the mean of all events. Such increase in extreme events over the course of years means that natural variability is being dominated by global warming, and causing a continuously shifting climate pattern.
Extreme events include heat, flooding, rainfall rates, drought, and wildfires. All of these occurrences have been increasing the frequency and severity around the world because of climate change. In addition, there is evidence that because of the high rate of warming of the Arctic, the mid-latitude jet stream has become weaker with increased amplitude extremes, leading to short-term and longer-term patterns favorable for extreme conditions at the surface. For example, high amplitude ridges of high pressure which do not move much or reform constantly can lead to extended periods of drought and extreme heat (while other areas downstream may receive cooler temps but heavy rainfall and flooding. This is actually something that is observable on meteorological timescales. Dr. Stefan Rahmstorf discusses the increases in extreme events from climate change in a lecture HERE.
One thing I must emphasize with understanding the impacts of global climate change is that it is impacting the environments of our world now and continue to accelerate in the coming years and decades (assuming no major changes are done). Global warming…the primary force of climate change, caused by our immense release of greenhouse gasses from fossil fuels…is the dominate force behind the rate of change in climate behavior. According to the Intergovernmental Panel on Climate Change in their 5th assessment, the world should actually be experiencing anomalous COOLING right now, but instead we have warmed Earth above and beyond natural long term global temperature variability. So when people ask “Did global warming cause (insert extreme weather event)?”, it is the wrong question. Climate looks at a collection of events for a trend. What is clear is that global warming is NOW causing a statistically significant increase in extreme events and will continue to do so. There is no “new normal” but only a continuous “ramping up” of the Earth’s natural variability toward greater extremes relative to the beginning of the Industrial Revolution, with greater impacts as humanity leaves the stable global climate in existence since the beginning of civilization.
This may be something many do not appreciate, but it is factual. Human civilization has changed Earth’s climate system to the point that we as humans are turning up the “thermostat” and started a multi-centennial experiment in geoengineering. Heat, drought, flooding, rainfall rates, wildfire events, and jet stream amplitudes, as a result, have all increased significantly in just the past 30 yrs.
If the climate were a piece of music…think of Earth’s relatively short-term natural cycles as the melody and global warming as the dominating background harmony from which the melody plays over. If the harmony changes keys, the melody will respond and shift accordingly.
In Part 3, I’ll discuss the projected future impacts of climate change being actively researched (and some already happening) such as food security, human health and living space.