Citat:
Ursprungligen postat av
Siegfrid
Lite grundläggande kemistudier kanske hjälper dig att förstå varför just pH är det relevanta måttet, samt hur buffring faktiskt fungerar.
Hint: buffersystemet i haven är inte statiskt utan drivet av biologiska processer, det regenererar sig själv så länge som det finns organiskt liv.
Bara 0,2 pH-sänkning? Det var klent, jag höjer alarmnivån till 0,4 pH. Ungefär lika trovärdigt det.
https://www.climate.gov/news-features/featured-images/ocean-acidification-today-and-future
Klent, i förhållande till vad? 0.4 säger bara alarmister som inte kan tänka sig annat är rcp8.5 - scenariot.
Citat:
Ursprungligen postat av
Trumpetflugan
Det som är relevant är hur känsligt (livet i) haven är för dessa förändringar. PH:t väntas sjunka ytterligare 0.2 enheter till år 2100 och det stannar ju inte där. Trenden är också av större betydelse än det momentana värdet just idag, eftersom den talar om vart vi är påväg.
https://www.smhi.se/en/research/research-news/ocean-ph-value-decreasing-1.27710
*Det fetade har du ännu inte tagit hänsyn till.
*PH-skalan är som tidigare påpekats logaritmisk. I dessa sammanhang talar man ofta om procent.
The ocean continues to acidify at an unprecedented rate in Earth’s history.
*Latest research indicates the rate of change may be faster than at any time in
the last 300 million years.
*As ocean acidity increases, its capacity to absorb CO2 from the atmosphere
decreases. This decreases the ocean’s role in moderating climate change.
* Species-specific impacts of ocean acidification have been seen in
laboratory and field studies on organisms from the poles to the tropics.
Many organisms show adverse effects, such as reduced ability to form
and maintain shells and skeletons, as well as reduced survival, growth,
abundance and larval development. Conversely, evidence indicates that
some organisms tolerate ocean acidification and that others, such as some
seagrasses, may even thrive.
* Within decades, large parts of the polar oceans will become corrosive to the
unprotected shells of calcareous marine organisms.
* Changes in carbonate chemistry of the tropical ocean may hamper or
prevent coral reef growth within decades.
* The far-reaching effects of ocean acidification are predicted to impact food
webs, biodiversity, aquaculture and hence societies.
* Species differ in their potential to adapt to new environments. Ocean
chemistry may be changing too rapidly for many species or populations to
adapt through evolution.
* Multiple stressors – ocean acidification, warming, decreases in oceanic
oxygen concentrations (deoxygenation), increasing UV-B irradiance due to
stratospheric ozone depletion, overfishing, pollution and eutrophication
– and their interactions are creating significant challenges for ocean
ecosystems.
* We do not fully understand the biogeochemical feedbacks to the climate
system that may arise from ocean acidification.
* Predicting how whole ecosystems will change in response to rising CO2
levels remains challenging. While we know enough to expect changes in
marine ecosystems and biodiversity within our lifetimes, we are unable to
make reliable, quantitative predictions of socio-economic impacts.
* People who rely on the ocean’s ecosystem services are especially vulnerable
and may need to adapt or cope with ocean acidification impacts within
decades. Shellfish fisheries and aquaculture in some areas may be able to
cope by adjusting their management practices to avoid ocean acidification
impacts. Tropical coral reef loss will affect tourism, food security and
shoreline protection for many of the world’s poorest people.
*170 %: The projected increase in ocean acidity by 2100 compared with
preindustrial levels if high CO2 emissions continue (RCP* 8.5).
*The current rate of acidification is over 10 times faster than any
time in the last 55 million years.
http://www.igbp.net/download/18.30566fc6142425d6c91140a/1385975160621/OA_spm2-FULL-lorez.pdf