• úvod
  • témata
  • události
  • tržiště
  • diskuze
  • nástěnka
  • přihlásit
    registrace
    ztracené heslo?
    TUHOKlimaticka zmena / Thank you so much for ruining my day
    YMLADRIS
    YMLADRIS --- ---
    Insects face ‘death by a thousand cuts’

    In the introduction to a special issue of PNAS that throws light on insect decline, ecologists do not mince words: “Nature is under siege,” they write. “Most biologists agree that the world has entered its sixth mass extinction event.” In a bid to provide a scientifically grounded assessment of insect population trends, the journal offers 11 papers that delve into every aspect of the issue.

    One of the challenges is going beyond “the overwhelming sense that something sinister is afoot” and gathering clear, comprehensive data on insect abundances over time. There are only a handful of long-term monitoring studies of insect populations. So entomologists have turned to plumbing other historical data for signals of change.

    PNAS special issue introduction | 30 min read & PNAS feature | 15 min read
    Insect decline in the Anthropocene: Death by a thousand cuts | PNAS
    https://www.pnas.org/content/118/2/e2023989118
    TADEAS
    TADEAS --- ---
    Do we only have 60 harvests left? - Our World in Data
    https://ourworldindata.org/soil-lifespans

    Let’s focus on the ‘conventionally managed’ soils, shown in blue. These data are relevant for understanding many of the world’s farming practices. We will look at conservation techniques later.

    Many of these soils are thinning; some very quickly. 16% have a lifespan of less than 100 years if they continue to erode at their current rates. This is not a local problem: there are examples of soils with lifespans shorter than a century on all continents, including the United States, Australia, Spain, Italy, Brazil and China. The longevity of these soils is concerning and we should be acting quickly to preserve them.

    But the “60 harvests” claim is quite clearly false. More than 90% of conventionally managed soils had a ‘lifespan’ greater than 60 years. The median was 491 years for thinning soils. Half had a lifespan greater than 1,000 years, and 18% exceeded 10,000 years. There were also some soils that were not eroding at all. Where soil formation rates exceeded erosion rates, soils thickened.In fact, some were thickening – soil was forming quicker than it was eroding. In the bottom-right of the chart we see the rates of soil gain. 7% of conventionally managed soils were thickening.

    If we were to keep our land completely bare – by removing any vegetation and preventing any natural regrowth through pesticides – our soils could erode more quickly. One-third (34%) of bare soils had lifespans less than 100 years.

    There is no single figure for how many harvests the world has left because there is so much variation in the types, quality, and management of our soils. It’s just implausible that they would all be degrading at exactly the same rate. As these results show: some soils are eroding quickly while others are thickening

    TADEAS
    TADEAS --- ---
    The climate outsider tackling Britain’s global warming mission – POLITICO
    https://www.politico.eu/article/the-climate-outsider-tackling-britains-global-climate-mission/amp/

    “This is a very different COP. This is not a negotiating COP,” said Christiana Figueres, the former head of the U.N. Framework Convention on Climate Change.

    Rather than presiding over tortured debates on new international law, Sharma’s goal is to convince every country on earth to set a date for reaching net zero emissions, plus new climate targets for 2030. Under the 2015 Paris Agreement, they aren’t officially due to update their plans until 2025, but after scientists in 2018 produced evidence of the serious consequences of warming even 1.5 degrees — the world is already around 1.2 degrees hotter — many governments decided climate change was outpacing that time frame.

    An update was planned for last November, but the COP26 was shifted to this year thanks to the pandemic.
    PER2
    PER2 --- ---
    trosku o vodiku:
    Decoding the Hype Behind the Natural Gas Industry’s Hydrogen Push | DeSmog
    https://www.desmogblog.com/2021/01/14/decoding-hype-behind-natural-gas-industry-hydrogen-push
    TADEAS
    TADEAS --- ---
    How close are we to the temperature tipping point of the terrestrial biosphere? | Science Advances
    https://advances.sciencemag.org/content/7/3/eaay1052.full

    "The temperature tipping point of the terrestrial biosphere lies not at the end of the century or beyond, but within the next 20 to 30 years (Figs. 2 and 3, A to D). Given the temperature limits of land carbon uptake presented here, without mitigating warming, we will cross the temperature threshold of the most productive biomes by midcentury, after which the land sink will degrade to only ~50% of current capacity if adaptation does not occur. While biomes will eventually shift spatially in response to warming, this process is unlikely to be a smooth migration, but rather a rapid disturbance-driven loss of present biomes (with additional emissions of carbon to the atmosphere), followed by a slower establishment of biomes more suited to the emerging climate. Furthermore, the establishment of new biomes is unlikely to be complete without human intervention and will be limited by edaphic factors, especially nutrient availability. This further suggests that we are rapidly entering temperature regimes where biosphere productivity will precipitously decline."
    SHEFIK
    SHEFIK --- ---
    TUHO: tyhle tezit nebudou, tak by to melo bejt dobry

    V Krkonoších loni vysázeli 39 000 stromků, většinou listnáče - Ekolist.cz
    https://ekolist.cz/...ravodajstvi/zpravy/v-krkonosich-loni-vysazeli-39.000-stromku-vetsinou-listnace
    KEB
    KEB --- ---
    LINKOS: mně to neříkej, já jen doufám, že to ví ti správní v EU, protože zatím to tak nevypadá. počkáme si co vypadne z toho green zákona co chtějí schvalovat.
    LINKOS
    LINKOS --- ---
    KEB: tak samozřejmě, že nemůžem nahradit uhlí dřevem a provozovat ty samé elektrárny dal. Limit našich ekosystémů nás omezuje, nejsme to ohromné kvantum energie takhle produkovat, mužem mít jen malé elektrárny co budou třeba vyrábět teplo a elektřinu z místních zdrojů, co nám ekosystém dovolí a třeba jen v zimě. Proto potřebujem jednak snížit náročnost našich domu, našeho průmyslu a toto snížené množství energie produkovat skrze oze
    KEB
    KEB --- ---
    LINKOS: tohle neuvěřitelný kvantum dřeva IMHO nejde produkovat udržitelným způsobem.
    LINKOS
    LINKOS --- ---
    KEB: proto jsem říkal, že by EU měla vyžadovat certifikaci původu dřeva. Samozřejmě, že uhlobaroni co mají elektrárny na uhlí, je budou chtít používat dál a dávat tam štěpky. Dává to smysl, pokud sme schopni to dřevo produkovat, nedává to smysl, pokud to musíme vozit deštného pralesa, což platí ale i o té sóje.
    TUHO
    TUHO --- ---
    České lesy se staly významným emitentem skleníkových plynů. Připadá vám to divné, když planetu mají od globálního oteplení zachránit právě lesy, které by pohltily CO2 z průmyslových zdrojů? Tak ale vězte, že takový mechanismus funguje jen dočasně. Dokud lesy přirůstají, skutečně CO2 využívají k fotosyntéze a růstu dřeva. Pokud však růst přestanou, a jsou vytěženy a zpracovány, stanou se vlastně zdrojem CO2 do ovzduší, protože většina dřeva je rychle zase spotřebována a CO2 uvolněn.

    Jakub Hruška: České lesy se staly významným emitentem skleníkových plynů - Ekolist.cz
    https://ekolist.cz/...ntare/jakubn-hruska-ceske-lesy-se-staly-vyznamnym-emitentem-sklenikovych-plynu
    KEB
    KEB --- ---
    LINKOS: a my tady v evropě je k tomu kácení ještě víc motivujeme, abychom měli co pálit a hrajeme si na uhlíkovou neutralitu pálením dřeva. Ok. Tohle k té debatě o podpoře klimatických opatření veřejností patří taky, protože to nedává smysl.
    TADEAS
    TADEAS --- ---
    Farmer-managed natural regeneration as a land-restoration strategy: under what conditions does it work?
    https://www.worldagroforestry.org/...al-regeneration-land-restoration-strategy-under-what-conditions

    Scientists from World Agroforestry (ICRAF) and Wageningen University, Netherlands studying regeneration on farms in Burkina Faso and Ghana. They asked how regeneration is affected by human activities, land degradation and by nearby forests and trees.
    LINKOS
    LINKOS --- ---
    KEB: ani ne, ten prales kácejí aby tam pěstovali sóju, dřevo pak prodají. Oboje je destruktivní
    KEB
    KEB --- ---
    LINKOS: vození soji a vození megatun dřeva na spálení je trochu dost rozdíl nemyslíš?
    LINKOS
    LINKOS --- ---
    KEB: zajímavé na tom je, že na dřevní štěpku se teď začínají orientovat uhlobaroni. EU by měla rychle vyžadovat aspoň certifikát na udržitelně pěstované dřevo. Ale tak zatím nějak nevadí ani vozit sem sóju jako krmivo a ta má stejný původ.

    Tohle je pro naše snižování emisí zásadní věc, my ty propady emisí potřebujem, ale myslím, že by jsme měli začít u sebe a vytvořit více bezzasahovych míst na našem území
    KEB
    KEB --- ---
    Ne tohle není ekologie ani omylem. A časem se ukáže, že je ekologický zločin moderní doby

    V Kodani se topí dřevem z Amazonie, je to uhlíkově neutrální. Chybu ale dělá celá EU - Ekolist.cz
    https://ekolist.cz/...dani-se-topi-drevem-z-amazonie-je-to-uhlikove-neutralni.chybu-ale-dela-cela-eu
    TUHO
    TUHO --- ---
    The temperature dependence of global photosynthesis and respiration determine land carbon sink strength. While the land sink currently mitigates ~30% of anthropogenic carbon emissions, it is unclear whether this ecosystem service will persist and, more specifically, what hard temperature limits, if any, regulate carbon uptake. Here, we use the largest continuous carbon flux monitoring network to construct the first observationally derived temperature response curves for global land carbon uptake. We show that the mean temperature of the warmest quarter (3-month period) passed the thermal maximum for photosynthesis during the past decade. At higher temperatures, respiration rates continue to rise in contrast to sharply declining rates of photosynthesis. Under business-as-usual emissions, this divergence elicits a near halving of the land sink strength by as early as 2040.

    How close are we to the temperature tipping point of the terrestrial biosphere? | Science Advances
    https://advances.sciencemag.org/content/7/3/eaay1052
    LINKOS
    LINKOS --- ---
    GLOBETROTTER: jo, kdyby bylo možné se do EU dostat jen po souši, asi by sme neměli žádný problém. Na mnohých místech to ani není moc daleko
    Kliknutím sem můžete změnit nastavení reklam