Ilmastonmuutos

[ihan tavallinen]

Global Investment Firm Warns 7.8 Degrees of Global Warming Is Possible

The British firm wants clients to factor climate change into investment decisions.

A leading British global investment firm has a warning for its clients: If we keep consuming oil and gas at current rates, our planet is on course to experience a rise in global average temperatures of nearly 8℃ (14℉) by the end of the century. This would make Earth basically uninhabitable for humans.

Although this is the darkest scenario we've seen so far, there's reason for cautious optimism: the new projections point out that it's unlikely investors will simply ignore this risk, meaning that our present level of fossil fuel consumption could decrease.

Still, by current climate research standards, this is a pretty wild number. It is four times as high as the 'safe limit' for increasing temperatures caused by climate change, internationally recognised to be around 2℃ (3.6℉) above pre-industrial levels. Schroders, the British investment firm which controls assets worth $542 billion, released this forecast as part of a range of potential scenarios in its 'Climate Progress Dashboard' in late July.

The Climate Progress Dashboard has been developed, a briefing says, to "help investors base decisions on the outcomes that are likely, rather than those they would like to see." It attempts to assess the progress being made by governments and industry on meeting climate targets. It breaks down what would happen to global temperatures if we continue on our current business-as-usual course, based on 12 different measures.

Those measures include 'political ambition,' which looks at the existing pledges made by governments; progress from major corporations on issues like 'climate finance' (new investment in efforts to curb or adapt to climate change) and 'carbon prices' (taxing carbon dioxide emitters); technological progress on factors like renewable energy adoption; as well as the potential future impact of current levels of oil, gas and coal production if they continue.

Andrew Howard, Schroders' Head of Sustainability Research, told Motherboard that the firm's analysis is based on comparing current levels of action in these 12 areas to different emissions scenarios that would lead to either 2, 4, or 6℃ of global warming.

Those scenarios are based on projections from the International Energy Agency (IEA), which produces the world's most authoritative scientific studies on energy issues, so the reliability of the dashboard's forecasts is based ultimately on the IEA.

Effectively, the Schroders analysis works backwards from the IEA's scenarios. "By comparing the level of activity in a particular area, for example EV (electric vehicle) sales, to what it would need to be under different temperature scenarios, we can estimate the temperature rise consistent with observed activity," explained Howard.

Viewed in isolation, each of these measures suggests a certain level of temperature rise.

Even if existing carbon reduction pledges, for instance, are implemented, the dashboard says this would still lead to a 2.8℃ warmer world by 2100—which is already well over the 2℃ limit that many scientists deem as acceptable to avoid the worst effects of climate change.

Technological progress, however, is not keeping pace with government pledges. So current rates of renewable energy adoption, the dashboard suggests, would lead to a rise of 3.1℃.

Schroders finds that this rate puts us on course to hit a global average temperature rise of 7.8℃ by 2100, if nothing changes

When all the measures are averaged out, the dashboard's overall scenario reveals that based on current government and industry practice, we are heading for a 4℃ hotter world—still double the internationally-recognised 'safe limit' for climate change. However, the most alarming projection—and perhaps the most relevant in terms of assessing where the worst risk is—can be found in the fine print.

The scientific consensus, of course, recognizes that climate change is driven by carbon emissions released from burning fossil fuels. So the most important measure on the dashboard relates to the current rate of oil and gas production. Astonishingly, Schroders finds that this rate, as it stands, puts us on course to hit a global average temperature rise of 7.8℃ by 2100, if nothing changes.

It's not game over yet, though. According to the Schroders briefing to its clients about the dashboard, it represents "a snapshot" of where we stand, not a firm prediction of where we will end. The briefing clarifies that all measures on the dashboard, including oil and gas production which depends on a wide range of factors—supply, demand, the gas glut, geopolitics, developments in renewable energy and storage, and so on—will likely change over several decades.

"As a result, the dashboard conclusions must be seen as measures of the paths we are currently on, rather than conclusions on where we will end up," said Howard.

He confirmed to Motherboard that the current oil and gas scenario was derived from production data in BP's 2017 Statistical Review of World Energy report. "It's clear that much more hydrocarbons are [currently] extracted than what the IEA analysis in particular considers consistent with safe temperature rises," he said.

Schroders also warns that a 6 ℃ or above pathway would lead to "up to a 50% loss in global GDP." Of course, massive GDP losses are just one element. Scenarios developed by the UN's Intergovernmental Panel on Climate Change (IPCC) show that a 6 ℃ average temperature rise or above will lead rapidly to an increasingly uninhabitable planet.

Just some of the impacts we would see include the loss of most of the world's coral reefs; the disappearance of major mountain glaciers; the total loss of the Arctic summer sea-ice, most of the Greenland ice-sheet and the break-up of West Antarctica; acidification and overheating of the oceans; catastrophic sea-level rise swamping major cities from London to New York; the collapse of the Amazon rainforest; and the loss of Arctic permafrost; to name just a few.

Some of these ecosystem collapses could, according to NASA's former chief climate scientist James Hansen, trigger an out-of-control runaway warming process.

The briefing, and the dashboard itself, are both designed to inform investors of climate risks that analysts at Schroders believe are not being factored into investment decisions.

"Investors who are unprepared or who have relied on overly simplistic analysis risk losses and missed opportunities," the briefing explains. "This is why gauging the timing and depth of market discounts for climate impacts is as important as analysing their effect."

It also touted the closing gap between global ambition and political action. The dashboard does not set out what will inevitably happen, but what would happen if business-as-usual continues, so any progress would help. And current trends show clear signs of change.

"Clean energy technology in particular continues to power ahead without the political support it needed in the past. Costs of wind and solar have declined to the point where they are competitive with fossil fuels, even without subsidies."

But oil and gas companies, the briefing warns, have not caught up with this reality—at some point, though, they will have to get on board.

The dashboard shows unmistakably that our current pathway is heading to unprecedented disaster: but it also shows that there is a good chance this worst-case scenario can be averted, as some of the world's biggest investors begin to pay serious attention to the potential consequences of what will happen if we don't change course.

https://motherboard.vice.com/en_us/arti ... witter.com

[tauti]

enää pari vuosisataa siunattuun hiljaisuuteen

[pigra senlaborulo]

Ilmastonmuutos aiheuttaa tuhoisia luonnononnettomuuksia Afrikassa – Sierra Leone ja Kongo kärsivät viimeksi
https://yle.fi/uutiset/3-9790814?origin=rss

Kongolainen viranomainen ja brittiläinen tutkija toteavat, että ilmastonmuutos ja kaupungistuminen ovat katastrofien taustalla.

Mistä on kyse?

Sierra Leonessa mutavyöryn kuolonuhreja on kaivettu esiin jo noin 500.
Viime viikon maanantaina vuorenrinne romahti Regentin lähiön päälle lähellä pääkaupunki Freetownia ja hautasi alleen tuhansia taloja.
Myös Itä-Kongon Iturin maakunnassa osa vuoresta romahti ja maanvyöry jätti alleen 50 taloa viime viikon keskiviikkona.
Viranomaisten mukaan katastrofi on vaatinut todennäköisesti ainakin 200 kuolonuhria.
Sierraleonelaiset ja kongolaiset viranomaiset ovat pyytäneet kansainvälistä apua pelastustöihin.

Läntisen Afrikan Sierra Leonessa ja mantereen keskellä Kongon demokraattisessa tasavallassa on tapahtunut viikon sisällä kaksi tuhoisaa maanvyörymää. Paikoilla on välimatkaa 5 000 kilometriä, mutta taustasyy on sama – ilmastonmuutos.

Ilmaston muuttuminen ja ääri-ilmiöiden lisääntyminen pahentavat luonnononnettomuuksia Afrikassa. Sekä Sierra Leonessa että Kongossa maanvyöryjä edelsivät rankkasateet.

Pahenevat sateet aiheuttavat haasteita kaupunkisuunnittelijoille ja viranomaisille useissa maissa. Afrikan mantereen monissa osissa maankäytön suunnittelussa on ongelmia muutenkin korruption, heikon taloustilanteen ja huonojen liikenneyhteyksien takia.

Itä-Kongossa jyrkkä vuorenrinne romahti sateiden voimasta ja jätti alleen kalastajien leirin.

– Täällä Kongossa tiedämme, että ongelma on ilmastonmuutos. Ilmasto on tullut arvaamattomaksi, kongolainen ympäristöministeriön neuvonantaja sanoo Ranskan radiolle RFI:lle (siirryt toiseen palveluun).

Sateet alkoivat Iturin maakunnassa tänä vuonna kahta kuukautta tavallista aiemmin.

Eroosio ja kaupungistuminen pahentavat riskejä

Sateiden lisääntymisen takana ovat eroosio ja metsien katoaminen. Irtonainen maa lähtee helpommin tulvavesien mukaan.

Samalla kaupungistuminen lisää onnettomuusriskiä. Sierra Leonessa hallitus on yrittänyt estää ihmisiä muuttamasta tulvaherkille alueille, mutta turhaan.

– Sierra Leonessa ihmiset, sekä rikkaat, että köyhät, ovat pakkautuneet yhä korkeammalle vuorten rinteille, brittiläinen Africa Research Instituten tutkija Jamie Hitchen sanoo RFI:lle.

Kongossa ja Sierra Leonessa pelastustyöt kestävät vielä pitkään. Molemmat maat ovat pyytäneet kansainvälistä apua.

[Pasi Fist]

Markkinat ovat taas olleet eettisiä.

https://www.theguardian.com/business/20 ... esearchers

Exxon deliberately misled public on climate science, say researchers

Study of company documents, peer-reviewed papers and newspaper ads claims to show how the oil giant tried to cast doubt on climate science

ExxonMobil has knowingly misled the public for decades about the danger climate change poses to a warming world and the oil giant’s long-term viability, according to a peer-reviewed study.

An analysis of nearly 200 documents spanning decades found that four-fifths of scientific studies and internal memos acknowledged global warming was real and caused by humans.

At the same time a similar proportion of hundreds of paid editorials in major US newspapers over the same period cast deep doubt on these widely accepted facts.

The study also cites ExxonMobil calculations that capping global warming at under 2C – the goal enshrined in the landmark Paris climate accord – would impose sharp limits on the amount of fossil fuels that could be burned, and thus potentially affect the firm’s growth.

Both findings are relevant to ongoing investigations by state and federal attorneys general, along with the Securities and Exchange Commission, on whether the company deceived investors on how it accounts for climate change risk.

The new study was published on Wednesday in the journal Environmental Research Letters.

Earlier reporting by InsideClimate News unearthed the internal documents and came to much the same conclusion.

In response, the company – the largest oil producer in the United States, with revenue of $218bn last year – denied having led a four-decade disinformation campaign.

Exxon spokesman Scott Silvestri called the latest study “inaccurate and preposterous” and said the researchers’ goal was to attack the company’s reputation at the expense of its shareholders.

“Our statements have been consistent with our understanding of climate science,” he said.

The company also criticised journalists for having allegedly “cherry-picked” data in a way that unfairly put the company in a bad light, but the new study pushed back on that claim.

“We looked at the whole cherry tree,” Geoffrey Supran, a researcher at Harvard University and co-author of the study, told AFP.

“Using social science methods, we found a gaping, systematic discrepancy between what Exxon said about climate change in private and academic circles, and what is said to the public.”

As early as 1979, when climate change barely registered as an issue for the public, Exxon was sounding internal alarms.

“The most widely held theory is that... the increase in atmospheric CO2 is due to fossil fuel combustion,” an internal memo from that year read.

A peer-reviewed study by Exxon scientists 17 years later concluded that “the body of evidence... now points towards a discernable human influence on global climate”.

At the same time, however, the company was spending tens of millions of dollars to place editorials in the New York Times and other influential newspapers that delivered a very different message.

“Let’s face it: The science of climate change is too uncertain to mandate a plan of action that could plunge economies into turmoil,” Exxon said in 1997, as the Bill Clinton administration faced overwhelming opposition in Congress to US ratification of the Kyoto Protocol.

Natasha Lamb, managing partner of investment management firm Arjuna Capital, said the new analysis could bolster the lawsuits accusing ExxonMobil of deliberately downplaying climate change risks.

“The Harvard research shows systemic bias in sowing public doubt, while acknowledging the risks privately,” she said after reviewing the study’s main findings. “That is at the heart of the investigations.”

Lamb’s firm filed the first shareholder proposal in 2013 asking ExxonMobil to assess whether imposing a 2C limit on warming would result in the company not being able to exploit its reserves.

Those efforts were swatted down, but four years later a decisive 62% of shareholders called on ExxonMobil, in a non-binding vote last May, to detail how climate change will affect its future.

In three other lawsuits, coastal communities in California are suing 37 oil, gas and coal companies, including ExxonMobil.

Marin and San Mateo counties, along with the city of Imperial Beach, assert that these fossil fuel purveyors knew their product would cause sea level rise and coastal flooding but took no action to inform the public or curtail their carbon emissions.

The new study “confirms some of the central tenets of our cases,” said Vic Sher, a senior partner at Sher Edling and a lawyer in the case.

“We will prove that Exxon and the fossil fuel industry knew for decades that greenhouse gas pollution would case warming of the air and oceans, sea level rise, and other consequences,” he told AFP.

“The industry engaged in deception and denial while aggressively marketing and making enormous profits.”

[pigra senlaborulo]

Alaskan harmaakarhut ovat kääntyneet vegaaneiksi ilmastonmuutoksen takia - valitsivat marjat kalojen sijaan
http://www.iltalehti.fi/ulkomaat/201708 ... 2_ul.shtml

Marjojen kypsyminen tavallista aikaisemmin voi vaikuttaa koko ekosysteemin toimintaan ja hyvinvointiin.

Alaskan Kodiakinsaaren harmaakarhut ovat lopettaneet lohen syönnin ja valinneet pakon edessä tavallista aikaisemmin kypsyneet seljanmarjat, kertoo brittilehti The Telegraph.

Lämpötilojen nousu on saanut marjat kypsymään aikaisemmin, minkä seurauksena karhut ovat joutuneet valitsemaan marjojen ja kalojen välillä.

Karhut ovat normaalisti syöneet lohta alkukesästä ja jatkaneet tankkausta seljanmarjoilla myöhemmin niiden kypsyessä vasta elo- ja syyskuussa.

- Tässä on kyse aikataulun sekoittumisesta, ilmiötä tutkinut Oregonin yliopiston biologi William Deacy selittää.

Deacy sanoo tilanteen olevan kuin samaan aikaan tarjoiltu aamiainen ja lounas.

- Sinun on pakko valita aamiaisen ja lounaan välillä, sillä pystyt syömään vain tietyn määrän ruokaa kerralla.

Normaalisti alaskalaiset karhut syövät noin 75% koko lohikannasta. Tutkimuksen mukaan epätavallisen lämpimänä kesänä vuonna 2014 karhut eivät kuitenkaan olleet lähelläkään lohia kuhisevia jokia.

Kalojen sijaan karhut olivat syömässä seljanmarjoja, jotka vähäisemmän proteiinipitoisuutensa vuoksi lihottavat karhuja nopeammin.

Biologit varoittavat lämpenevän ilmaston ja karhujen muuttuvan käytöksen vaikuttavan koko ekosysteemiin.

Tutkimuksen mukaan muun muassa jokia ympäröivät metsät kärsivät, sillä karhujen ulosteen kasvustolle antamat ravinteet puuttuvat.

[Doctor Muñiz]

Karhu ei enää paskokaan metsään.

[Aloysius Kärppä]

Markkinat ovat taas olleet eettisiä.

https://www.theguardian.com/business/20 ... esearchers

Exxon deliberately misled public on climate science, say researchers

Study of company documents, peer-reviewed papers and newspaper ads claims to show how the oil giant tried to cast doubt on climate science

ExxonMobil has knowingly misled the public for decades about the danger climate change poses to a warming world and the oil giant’s long-term viability, according to a peer-reviewed study.

An analysis of nearly 200 documents spanning decades found that four-fifths of scientific studies and internal memos acknowledged global warming was real and caused by humans.

At the same time a similar proportion of hundreds of paid editorials in major US newspapers over the same period cast deep doubt on these widely accepted facts.

The study also cites ExxonMobil calculations that capping global warming at under 2C – the goal enshrined in the landmark Paris climate accord – would impose sharp limits on the amount of fossil fuels that could be burned, and thus potentially affect the firm’s growth.

Both findings are relevant to ongoing investigations by state and federal attorneys general, along with the Securities and Exchange Commission, on whether the company deceived investors on how it accounts for climate change risk.

The new study was published on Wednesday in the journal Environmental Research Letters.

Earlier reporting by InsideClimate News unearthed the internal documents and came to much the same conclusion.

In response, the company – the largest oil producer in the United States, with revenue of $218bn last year – denied having led a four-decade disinformation campaign.

Exxon spokesman Scott Silvestri called the latest study “inaccurate and preposterous” and said the researchers’ goal was to attack the company’s reputation at the expense of its shareholders.

“Our statements have been consistent with our understanding of climate science,” he said.

The company also criticised journalists for having allegedly “cherry-picked” data in a way that unfairly put the company in a bad light, but the new study pushed back on that claim.

“We looked at the whole cherry tree,” Geoffrey Supran, a researcher at Harvard University and co-author of the study, told AFP.

“Using social science methods, we found a gaping, systematic discrepancy between what Exxon said about climate change in private and academic circles, and what is said to the public.”

As early as 1979, when climate change barely registered as an issue for the public, Exxon was sounding internal alarms.

“The most widely held theory is that... the increase in atmospheric CO2 is due to fossil fuel combustion,” an internal memo from that year read.

A peer-reviewed study by Exxon scientists 17 years later concluded that “the body of evidence... now points towards a discernable human influence on global climate”.

At the same time, however, the company was spending tens of millions of dollars to place editorials in the New York Times and other influential newspapers that delivered a very different message.

“Let’s face it: The science of climate change is too uncertain to mandate a plan of action that could plunge economies into turmoil,” Exxon said in 1997, as the Bill Clinton administration faced overwhelming opposition in Congress to US ratification of the Kyoto Protocol.

Natasha Lamb, managing partner of investment management firm Arjuna Capital, said the new analysis could bolster the lawsuits accusing ExxonMobil of deliberately downplaying climate change risks.

“The Harvard research shows systemic bias in sowing public doubt, while acknowledging the risks privately,” she said after reviewing the study’s main findings. “That is at the heart of the investigations.”

Lamb’s firm filed the first shareholder proposal in 2013 asking ExxonMobil to assess whether imposing a 2C limit on warming would result in the company not being able to exploit its reserves.

Those efforts were swatted down, but four years later a decisive 62% of shareholders called on ExxonMobil, in a non-binding vote last May, to detail how climate change will affect its future.

In three other lawsuits, coastal communities in California are suing 37 oil, gas and coal companies, including ExxonMobil.

Marin and San Mateo counties, along with the city of Imperial Beach, assert that these fossil fuel purveyors knew their product would cause sea level rise and coastal flooding but took no action to inform the public or curtail their carbon emissions.

The new study “confirms some of the central tenets of our cases,” said Vic Sher, a senior partner at Sher Edling and a lawyer in the case.

“We will prove that Exxon and the fossil fuel industry knew for decades that greenhouse gas pollution would case warming of the air and oceans, sea level rise, and other consequences,” he told AFP.

“The industry engaged in deception and denial while aggressively marketing and making enormous profits.”

Tää on hyvä. Exxon TIESI että paska saattais suunnata kohti tuuletinta; tykitti silti miljoonilla advertoriaaleja JOKA VIIKKO New York Timesiin ym. vuosikymmenien ajan. Gg wp.

https://www.theverge.com/2017/8/23/1619 ... vard-study

[Elmeri suosittelee]

Ohhoh, tää on kova teesi. Jenkkien tekemä intiaanien kansanmurha aiheutti ilmastonmuutoksen

Did the Deaths of 50 Million Indians Cause Climate Change?

Steve Russell • September 15, 2017
No historian seriously questions that the European invasion of the Americas resulted in millions of deaths. The serious debate has been how many millions. What if it was enough millions to change the carbon dioxide (CO2) content in the atmosphere and therefore the climate and ultimately the geology of the Earth?

Simon Lewis and Mark Maslin, British geographers writing in Nature, have proposed that a massive die-off of Indigenous Peoples in the Americas has left enough permanent global evidence to define a new geological epoch, the Anthropocene. In this seminal study, they examine the Industrial Revolution and the detonation of atomic bombs as potential geological markers.

The Industrial Revolution, they conclude, happened too unevenly to provide worldwide physical evidence pointing to a reasonably specific date. The atomic bomb arrived in 1945 with worldwide geological evidence of permanent change peaking in 1964.

Lewis and Maslin reject 1964 largely because the date is so recent that the changes that began in 1945 are still playing out. I would add that the international treaty banning atmospheric nuclear tests went into effect in 1963, and the geological impact of radiation can be radically changed by new countries joining the nuclear club or a war breaking out among the current members. Either of these events would destroy the geological usefulness of 1964.

This leaves the collision between the so-called Old World and New World, which Lewis and Maslin claim caused a dip in atmospheric CO2 that is measurable in many ways worldwide. All measurements point to 1610 as the low point in the dip. The cause of the dip has a great impact on historians’ arguments over American Indian body count from contact with Europeans. While this evidence does not quiet disputes about the intent of the colonists, modern Indians would consider just knowing the approximate body count from physical evidence an improvement in the historical narrative.

How do dead Indians cause lower atmospheric CO2? If we all met the stereotype of hunter-gatherers before Europeans showed up, a die-off would not have a global impact. A charitable view of that stereotype would be that it was a mistake caused by more hunter-gatherers surviving European diseases because, unlike their sedentary farmer cousins, they had very little direct contact with the colonists and therefore less opportunity to be infected.

When farmers die off, their fields go fallow. When the fields go fallow, forests take over, and forests are gigantic carbon sinks, sucking up CO2. Theoretically, if the deaths were enough to move the CO2 in the entire atmosphere, it ought to be possible to “reverse engineer” the body count. Lewis and Maslin started with body counts that match existing scholarship.

The calculation in the Nature article is that the European invasion caused the deaths of approximately 50 million people farming 1.3 hectares per person. Removal of that many people from that much land should sequester between 7 and 14 petagrams of carbon over 100 years, the difference in numbers having to do with how much of the farming was “slash and burn” agriculture, which gives off more CO2.

They suggest that maximum human mortality would happen decades after first contact in 1492 and maximum carbon uptake from the fallow farms would take another 20-50 years, suggesting a date between 1550 and 1650. Ice core CO2 measurements narrow the date to 1610.

This is not a completely abstract dispute. Lewis and Maslin are arguing for recognition of a Global Stratotype Section and Point (GSSP, less formally known as a “golden spike”) and/or a Global Standard Stratigraphic Act (GSSA). Recognition of these markers requires a consensus in the scientific community.

In 2013, the International Union of Geological Sciences (IUGS) convened a group of scholars charged to decide by 2016 whether the Holocene is over and the Anthropocene has begun. The best evidence of that is a “golden spike,” and the Nature article is aimed at convincing the IUGS that we have a consensus.

Once that consensus is reached, the collision of Europe and the Americas becomes the working paradigm, the method of describing research going forward. What is at stake is the boundary of the Anthropocene, the epoch of humans. From our point of view, genocide will be recognized as a source of anthropogenic climate change. Since the climate change happened, the genocide will be impossible to deny.

https://indiancountrymedianetwork.com/h ... ign=buffer

[Doctor Muñiz]

Conquistadorit, nuo tunnetut jenkkiperkeleet. Ymmärsitkö muuten minkälaiseen ilmastonmuutokseen tossa viitattiin?

[Elmeri suosittelee]

Conquistadorit, nuo tunnetut jenkkiperkeleet. Ymmärsitkö muuten minkälaiseen ilmastonmuutokseen tossa viitattiin?

En ole ehtinyt lukemaan artikkelia vielä

[Doctor Muñiz]

Joo, huomasin.

[Doctor Muñiz]

Rip maailma:

Pelottava tutkimustulos: sademetsät [sic] aiheuttavat nyt enemmän ilmastopäästöjä kuin poistavat – puustoa hakattu liikaa

Sademetsien yhtenäinen lehtikatto on haitannut satelliittihavaintoja osittain vaurioituneista metsistä.

Trooppisten sademetsien tila on heikentynyt niin paljon, etteivät ne enää hillitse ilmastonmuutosta, vaan kiihdyttävät sitä. Tämän kuohuttavan tutkimustuloksen ovat saaneet Bostonin yliopiston ja tutkimuslaitos Woods Holen tutkijat pitkäaikaisen tutkimustyön seurauksena.

Alun perin Science -tiedelehdessä julkaistusta tutkimuksesta uutisoi mm. brittiläinen The Guardian.

Tutkijat liikkuivat 12 vuoden ajan maastossa ja tutkivat myös sademetsistä tehtyjä satelliitti- ja lasermittauksia.

Tutkijoiden keskeinen havainto oli se, että metsä saattaa olla vakavasti vaurioitunut, vaikka se satelliitista kuvattuna näyttää yhtenäiseltä.

Kun ilmastotutkijat tekivät arvioitaan metsämaan aiheuttamista ilmastopäästöistä, mittauksessa otettiin huomioon vain täysin avohakatut alueet. Uusi havainto oli, että pienimuotoisempikin puuston poisto muuttaa olennaisesti metsän kykyä imeä itseensä hiilidioksidia.

Sademetsän tiivis lehväkatto peittää esimerkiksi puiden osittaisen poistamisen, kuivuuden, metsäpalojen ja metsästyksen aiheuttamat vauriot. Puiden määrä on vähentynyt, mikä on supistanut myös mm. luonnon lajikirjoa, biodiversiteettiä.

Joissakin tapauksissa muutosten seurauksena puuston kyky toimia hiilinieluna on myös kasvanut.

Vaurioituneet metsät ovat päästölähteitä

Bostonin yliopiston ja Woods Holen tutkimuslaitoksen tutkimuksesta ilmenee, että tase on pahasti miinuksella. Kun aiemmin sademetsiä pidettiin suurena päästönieluna, tällä hetkellä sademetsät aiheuttavat vuosittain lisäpäästöjä 425 teragrammaa, mikä on yhtä paljon kuin koko paljon kuin koko Yhdysvaltain auto- ja rekkaliikenne.

– Tiesimme, että metsien tilan heikkeneminen oli ongelma, mutta emme tienneet, että kuinka suuri se oli, totesi yksi tutkimuksen johtavista kirjoittajista Wayne Walker.

– Kun katson näitä lukuja ja karttaa, missä muutoksia on tapahtunut, olen sokissa, sanoi The Guardianille tutkimusjohtaja Alessandro Baccini, jolla on 2-vuotias lapsi.

– Lapseni ei tule näkemään juurikaan näitä metsiä. Tällä muutosvauhdilla niitä ei pian enää ole.

Tutkijat painottavat, että haitallisen muutoksen pysäyttämiseksi vanhojen, paljon hiiltä itseensä sitoneiden metsien säästäminen on entistäkin tärkeämpää. Maaoikeuksien palauttaminen alkuperäiskansoille olisi tutkijoiden mukaan tehokkain keino säästää sademetsiä.

Tästä huolimatta monessa maassa on tooimittu täsmälleen päinvastoin. Esimerkiksi Brasiliassa ja Kolumbiassa hakkuut lisääntyvät nopeasti.

https://yle.fi/uutiset/3-9857591

[valtion virallinen tili]

^tota olin tulossa. Jotenki kävi masentamaan ja turhauttamaan ku ton luki.

[Darkthronen tunnettu Hiisi]

RIP maailma pt. 2

http://www.popularmechanics.com/science ... -ice-hole/

A Giant Hole Just Appeared in Antarctica
And scientists have no idea what's causing it.

Something strange is happening in Antarctica. A giant hole the size of Lake Superior has opened up in the ice, and scientists aren't sure exactly what is causing it.

Holes in the ice are common enough that there's a name for them: polynias, borrowed from the Russian word for water surrounded by sea ice. But this particular polynia is unique for two reasons. It's very large, and it's located far away from the warmer ocean water.

"This is hundreds of kilometers from the ice edge," said atmospheric physicist Kent Moore to Motherboard. "If we didn't have a satellite, we wouldn't know it was there."



Most polynias are easy to explain. They tend to form when a current of warm ocean water from underneath the ice melts a small amount, forming a region of no water. But this polynia is so far from the coast that it's unlikely to have arisen in this way.

This particular polynia has also appeared in this location twice before, once last year and once in the 1970s. This means that whatever is causing it has some sort of repetitive nature, which could help scientists uncover what is happening.

And if scientists do figure out what is causing this particular polynia, it will shed some light on how Antarctica will change over the next few years. The continent is changing rapidly, with melting ice, collapsing glaciers, and awakening volcanoes making it difficult to predict where Antarctica is headed. Understanding what's causing this polynia could help scientists put some of the pieces together.

[pigra senlaborulo]

Tutkijat löysivät valtavan virheen muinaisten valtamerien lämpötila-arvioissa – ilmastonmuutos saattaa olla luultua pahempaa
https://tekniikanmaailma.fi/tiede/tutki ... 93cc21-500

Ilmastonmuutos saattaa olla luultua pahempaa, koska valtameren aiempaa lämpötilaa on luultavasti arvioitu dramaattisesti väärin, kertoo torstaina julkaistu tutkimus.

Torstaina julkaistussa eurooppalaisessa tutkimuksessa todetaan, että valtamerten aikaisempia lämpötiloja arvioineissa malleissa on pahoja virheitä, minkä vuoksi muinaisten valtamerten lämpötila-arviot saattavat heittää jopa 15 asteella.

Tällaiseen johtopäätökseen on päätynyt tutkimus, jossa ovat olleet mukana Ranskan kansallinen tiedetutkimuskeskus CNRS, Sorbonnen ja Strasbourgin yliopistot sekä sveitsiläisiä tutkijoita Lausannen yliopistosta ja EPFL-tutkimuslaitoksesta.

Tutkimuksen tulokset on julkaistu Nature Communications -lehdessä.

Uusi tutkimus väittää, että valtameret olivat ennen paljon kylmempiä kuin on tähän asti arvioitu. Tämä puolestaan tietysti tarkoittaisi, että maapallon nykyinen lämpenemistrendi on paljon luultua voimakkaampi.

Tutkijat ovat arvioineet kriittisellä silmällä uudelleen metodia, jota on perinteisesti käytetty valtamerien lämpötilan arviointiin kaukaisessa menneisyydessä.

Valtamerien lämpötilojen mittaamisessa on hyödynnetty pienien meressä eläneiden huokoseläinten fossiileja. Mittauksissa on hyödynnetty happi-18- ja happi-16-isotooppien välistä suhdetta.

Metodin ongelmaksi on paljastunut, että aiemmin täydellisesti säilyneet fossiilit eivät ole olleetkaan täydellisesti säilyneitä, sanoo CNRS:n mineraalitutkija Sylvain Bernard tiedotteessa.

Aiemmissa laskelmissa on pitkään oletettu, että merenpohjan lämpötila on ollut 100 miljoonaa vuotta sitten jopa 15 astetta korkeampi kuin nyt. Uudet laskelmat viittaavat siihen, että meret ovat olleet ennen siis paljon luultua kylmempiä ja että merten lämpötila on pystynyt suhteellisen vakaana.

”Jos me olemme oikeassa, tutkimus asettaa kyseenalaiseksi muinaisilmastollisen tutkimuksen vuosikymmenien ajalta”, sanoo Lausannen yliopiston professori Anders Meibom.

”Valtameret peittävät 70 prosenttia planeetastamme. Ne näyttelevät tärkeää roolia maapallon ilmastossa. On tärkeää ymmärtää, miten niiden lämpötilat ovat vaihdelleet geologisella ajanjaksolla, jos haluamme ymmärtää ja ennakoida ilmaston kehitystä nykyistä tarkemmin.”

Anders Meibomin mukaan tutkijat ovat jo alkaneet laskea ja arvioida uudelleen merilämpötilojen muinaista kehitystä. Avuksi tässä aiotaan ottaa muita meressä eläneiden organismien fossiileja.