Name: ancient clues to climate change
Uploaded: 2019-03-11T09:21:43.000Z
Duration: 1 min 50 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

ecosystems-interactions-energy-and-dynamics

Ecosystems- Interactions, Energy, and Dynamics

LS.Bio.5.2

Global Climate Change

- [Docent] De aarde heeft door de geschiedenis heen periodes van opwarming en afkoeling gekend. In de laatste eeuwen is echter sprake van een drastische stijging van de wereldwijde temperatuur buiten de cyclische normen van de aarde om. Opwarming vindt plaats als broeikasgassen zoals koolstofdioxide zich ophopen tussen de aarde en de ozonlaag.

Koolstofdioxide kan zonne-energie van lange infrarode golflengtes absorberen, en zo voorkomen dat die terugreist naar de ruimte, waardoor de temperatuur in de atmosfeer stijgt. Hoewel dit een natuurlijk proces is, het broeikaseffect, is de sterke toename en de hoeveelheid koolstofdioxide in de atmosfeer als gevolg van verbranding van kolen en olie, dat niet. De gevolgen van deze temperatuurstijging zijn wereldwijd te zien.

In het Arctisch gebied bijvoorbeeld, smelten ijskappen, met als gevolg zeespiegelstijging en overstroming van eilanden. Dit bedreigt niet alleen kuststeden, maar kan ook leiden tot extremere weersomstandigheden, zoals droogtes orkanen, en zware stormen. Ook migratie- en broedgedrag van veel dieren vindt eerder in het jaar plaats dan tientallen jaren geleden en het verspreidingsgebied van soorten neemt af.

De opwarming van de aarde wordt steeds vaker erkend door sceptici, en de groei van duurzame praktijken in de industrie kan kansen bieden om de menselijke impact terug te draaien en de ernstige gevolgen van de klimaatverandering te voorkomen.

wereldwijde klimaatverandering

Gedurende haar 4,5 miljard jaar durende geschiedenis heeft de aarde periodes van opwarming en afkoeling meegemaakt. De huidige drastische stijging van de mondiale temperaturen ligt echter ver buiten de cyclische normen van de aarde, en het bewijs voor door de mens veroorzaakte mondiale klimaatverandering is overtuigend. Paleoklimatologie, de studie van oude klimaatomstandigheden, levert ruimschoots bewijs voor door de mens veroorzaakte mondiale klimaatverandering door recente omstandigheden te vergelijken met die in het verleden.

<h4>Afgelopen perioden van opwarming en afkoeling</h4>

Alleen al in de afgelopen 650.000 jaar zijn er zeven cycli van opmars en terugtrekking van de gletsjers geweest. Ruim 11.000 jaar geleden kwam er abrupt een einde aan de meest recente ijstijd—wat het begin markeerde van ons moderne klimaattijdperk, het geologische tijdperk van het Holoceen. De meeste historische klimaatveranderingen worden in relatie gebracht met kleine variaties in de baan van de aarde, waardoor de hoeveelheid zonnestraling die de aarde ontvangt, verandert.

<h4>Paleoklimatologie</h4>

Paleoklimatologie is de studie van klimatologische omstandigheden en hun oorzaken en gevolgen in het geologische verleden van de aarde. Paleoklimatologen gebruiken een verscheidenheid aan wetenschappelijke methoden om de vroegere omstandigheden van het klimaat en het atmosferische systeem op aarde af te leiden.

<h4>Gegevens over ijskernen</h4>

IJskernmonsters genomen van dikke berggletsjers en poolijskappen kunnen informatie onthullen over de mondiale klimaatverandering. Seizoensgebonden pauzes in de ijsaccumulatie kunnen leiden tot waarneembare lagen in ijskernen. Deze lagen kunnen worden gebruikt om een chronologie vast te stellen, waarbij de onderste lagen de oudste zijn. Onderzoekers kunnen vervolgens de eigenschappen van het ijs en het daarin opgesloten materiaal (bijvoorbeeld luchtbellen en verhoudingen van zuurstof- en waterstofisotopen) analyseren om het oude klimaat van de aarde te reconstrueren. Het Europese project voor het boren van ijs op Antarctica analyseerde vulkanische as die vastzat in ijskernen van Antarctica om een gedetailleerd overzicht te geven van de vulkanische geschiedenis van het Holoceen. Dit record onthulde 96 uitbarstingen tijdens het Holoceen, waarvan 33 in de afgelopen 2000 jaar.

<h4>Dendroklimatologie</h4>

Wetenschappers kunnen het klimaat in het verleden ook bestuderen door jaarlijkse boomringen te onderzoeken – een vakgebied dat dendroclimatologie wordt genoemd. In wezen zijn boomringen breder onder gunstige omstandigheden en smaller tijdens barre tijden. Boomringen kunnen nauwkeurig worden gedateerd door ringen van monster tot monster te matchen - zelfs monsters van archeologische opgravingen. Hoewel de dendroklimatologie beperkingen kent, zijn boomringen nuttige klimaatproxy's die kunnen worden gebruikt om klimaatregistraties met hoge resolutie voor specifieke geografische locaties te creëren.

Wereldwijde klimaatverandering

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global ...

Education

JoVE Core

Biologie

Ecology

Ecologie

Biodiversity and Conservation

Biodiversiteit en natuurbescherming

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

ancient clues to climate change

Ancient climate clues help scientists track global climate change. Paleoclimatology is the study of climate conditions in Earth’s past and the causes and effects behind them. By comparing recent climate patterns with older records, researchers can find strong evidence for human-caused warming.

Earth’s climate has changed many times over its 4.5 billion year history. In the last 650,000 years, there have been seven cycles of glacial advance and retreat. The most recent ice age ended more than 11,000 years ago and began the Holocene, the modern climate era. Many earlier changes were linked to small shifts in Earth’s orbit that altered the amount of solar radiation reaching the planet.

Paleoclimatologists use several scientific methods to study the past climate and atmosphere. One major source is ice core data from thick mountain glaciers and polar ice sheets. Seasonal pauses in ice buildup create layers in the ice, and the lowest layers are the oldest. Scientists can study the ice itself and the trapped material inside it, such as air bubbles and ratios of oxygen and hydrogen isotopes, to reconstruct ancient climate conditions.

Ice cores can also preserve volcanic ash. The European Project for Ice Coring in Antarctica used ash trapped in Antarctic ice cores to build a detailed record of Holocene volcanic history. That record showed 96 eruptions during the Holocene, including 33 eruptions in the last 2,000 years. Another useful climate proxy is tree rings. Dendroclimatology, the study of annual tree rings, shows that rings are wider in favorable conditions and narrower in harsh ones. Tree rings can be matched and dated across samples, even from archaeological digs, and they help create high-resolution climate records for specific places, although the method has limits.

Ancient Clues to Climate Change

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global climate change

Ancient climate clues help scientists track global climate change. Paleoclimatology is the study of climate conditions in Earth’s past and the causes and effects behind them. By comparing recent climate patterns with older records, researchers can find strong evidence for human-caused warming. Earth’s climate has changed many times over its 4.5 billion year history. In the last 650,000 years, there have been seven cycles of glacial advance and retreat. The most recent ice age ended more than...

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what is climate?

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key terms and concepts

Explore how ice cores and tree rings reveal Earth’s past climate. Learn how paleoclimatology helps scientists study ancient warming, cooling, and volcanic history.

Ancient Clues to Climate Change | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

Ancient Clues to Climate Change

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