Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present
In this study, Zachos et al., focuses on the constant
changes in Earth’s climate that have taken place in the Cenozoic Era; a period
of Earth’s history which was incredibly dynamic in terms of climate. This is of
particular importance because, within this time frame (65 My), Earth’s climate shifted
from periods of warm, ice-free poles to periods of severe cold and expansive continental
ice-sheets. This is in accordance with forces that are understood to drive and
affect long-term climate, which include changes in Earth’s eccentricity, obliquity,
and procession. All these tend to remain relatively constant for millions of
years, and thus provide predictable ways to describe and predict past climate. Furthermore,
the climatic changes caused by the forces listed above are also influenced by tectonic
plate-induced changes in concentrations of atmospheric greenhouse gases,
topography, continental geography, and locations of oceanic gateways, all of
which change “gradually…[and] unidirectionally” within a million-year time
scale. Plate tectonic events in the last 65 million years such as the North
Atlantic rift volcanism, the collision of India and Asia, as well as the
closure of the Central American Seaway have all triggered monumental changes in
global climate system dynamics. Zachos et al. suggest that all of these factors,
together, could have caused “rapid and extreme” climatic changes that took
place during the Cenozoic.
Additionally, reconstructing a timeline of Earth’s climate change
during the Cenozoic has been largely possible by analyzing deep-sea 18O
and 13C isotope
records, which have given insight into abrupt and “transient” shifts in climate.
These isotope record analyses have proven to be of great importance in developing
theories that can explain not only the mechanisms for climate change, but also
how these changes impacted environments. For this study specifically, Zachos et
al. compiled d18O
and d13C isotope
data for bottom-dwelling, deep-sea foraminifera from more than 40 Deep Sea
Drilling Project (DSDP) and Ocean Drilling Program (ODP) sites from various
time-periods of the Cenozoic, which were then compiled into one global deep-sea
isotope record. Deep sea carbon and oxygen isotope data provide very distinct
but essential pieces of information when reconstructing past climate history. Carbon
isotope data provides for a better understanding of global carbon cycle
perturbations, as well as changes in deep-sea circulation patters, while oxygen
isotope data gives insight into deep-sea temperatures and the volume of
continental ice. After compiling isotope data from DSDP and ODP sites, climate
evolution during the Cenozoic was divided into three categories: long term (~106
to 107 years), short-term [orbital-scale] (~104 to 105
years), and aberrations [event-scale] (~103 to 104 years).
One of the strongest findings in this data review is that
ice-sheets are incredibly sensitive to changes in Earth’s obliquity, regardless
of other boundary conditions or the location of ice sheets. Additionally, the data
confirmed that eccentricity oscillations during the pre-Pleistocene caused a
strong climatic response, and that changes due to eccentricity during the late
Pleistocene resulted in temperature changes and not in ice volume changes as was
previously thought. Lastly, this review provided further confirmation that
aberrations in global climate can be attributed to various mechanisms, some of
which are predictable, while others are not. This may explain their appearance
at a random distributions and frequencies. The authors suggest that future
research should concern global and regional scale changes associated with
aberration and transient climatic events, specifically in high latitudes,
tropics, or continental interiors, which are considered environmentally
sensitive regions.
Questions:
1.) In what ways do you think tectonic movement could influence climate conditions?
2.) How could the results obtained in the paper be expanded upon, or of relevance to other scientific disciplines?
- Italia Gonzalez, Andrew Maldonado, Nathan Allison
The paper says that tectonic movement can influence climate conditions by volcanism , opening of sea gateways, collisions of different land masses that can uplift mountain ranges and plateaus, and closing of sea ways.
ReplyDeleteThe results in this paper can be relevant to the ecology of the past because if we know the climate of a certain time we can infer how plants and animals lived and survived in this time. This can be especially important if we do not have a very good fossil record of this time.
I agree with what Jessica said about how tectonic plates could cause climatic conditions, but also to add that when plates move against one another it causes a lot of friction which could also result in the up-welling of gases or slight volcanism. The data obtained through this can be applied to other disciplines such as chemistry or biology to paint an even broader picture of climate during that time and possibly even further back.
ReplyDeleteCool paper that shows us how global events aren't always triggered by just one thing -- it's often a system of feedbacks that includes orbital, tectonic, and climatic events, and sometimes help from the biosphere. Also shows us just how cool and useful forams are! To add to the above answers to Question 1, scientists also think that mountain building/uplift events cause global cooling because tall mountains are physically and chemically weathered more quickly -- chemical weathering uses up carbon dioxide from the atmosphere, and lots of exposed rock will use up more CO2. Also the movement of plates will sometimes cause two (or more) continents to collide, cutting off ocean circulation in that area. This is what we learned in class might have caused the Permian extinction: the creation of Pangaea may have disturbed the ocean's circulation by forming right on the middle of the globe. Larger continents also produced more extreme seasons in both the interior of the continent and on the edges.
ReplyDeleteI would have to agree with Jessica and Adam that tectonic plates hold influence on the global climate by changes in volcanic activity and uplifts creating new ranges of land causing a difference in land area. This could lead to many biotic events that could alter atmospheric conditions altering climate. This information can aid in the knowledge of today's climate and conversational biology to see how fast our polar caps are melting in comparison to the past where ice free caps where present and how/why they were caused and in what time frame. The knowledge of past climate could also be beneficial to try to understand ecosystem reactions over the Cenozoic period and how future interactions could prevent climate changes or encourage them.
ReplyDeleteI really enjoyed Derek's point in using data from the past to infer about climate over the past and in the future. Using what we know about the movement of tectonic plates and their ability to influence our climate by a multitude of different ways, one of which is pointed out by many others, volcanism. We can use this date to piece together the changes in climate over the past millions of years as well as answer many questions people are having about what the future climate will be.
ReplyDeleteI thought the results of this paper had important implications because of what Agathe mentioned, that global events aren't always triggered by one thing. As mentioned in the paper, Zachos et al. provide a compiled record of global changes in ocean oxygen and carbon levels that they are able to tie to climatic, tectonic, and biotic events. This allows for a before and after picture of certain climate events. We can begin to get at causal factors for these events (as the authors do within the paper for numerous aberrations) and the result of these events. As mentioned by earlier posts, This can help us to understand the past (and to add to Adam's list, also applicable for Geologists) and the implications for our future (and has implications for Climatologists).
ReplyDeleteOne question I have is whether it would possible to provide a similar type of data set for specific regions to look at regional impacts. Perhaps there is not enough data to do so, or those regional data sets were what was able to be complied for this paper.
techtonic shifts only effect climate if landmasses move away or toward the poles. landmasses such as antarctic sits at the pole and has remained glaciated for millions of years. the presence of ice increases the albedo of the planet, provides a source for CO2 sequestration as phyto organisms are unable to release CO2 into the atmosphere when they die. if the land mass moves away from the pole less ice will be present and will influence warming. the research could go into greater detail as to what biological Carbon sinks exist
ReplyDeleteTectonic activity could have an effect on climate based on how the continents are placed, which could change ocean currents. For example, South America splitting off from Antarctica opened up a circus-polar seaway that thermally isolated Antarctica, allowing it to progressively become colder and colder. In addition, the combination of the Great American Interchange and the closing of the Tethys Sea closed off a circum-equitorial seaway, which reduced the amount of heat that the equatorial waters were absorbing before being diffused along a thermal gradient towards the poles.
ReplyDeleteThis paper goes to show that major ecological changes/uphevals are neverattributed to just one biotic or abiotic factor, and massive tectonic plate movements are responsible for much more than just merging continents or growing mountains. Volcanic activity, presence/absence of polar ice caps, CO2& O2 concentrations in athmosphere and oceans are all interwined and connected. Thats important because if we understand how it all ties in together we can gain a greater understanding of the ecology of past eras for which we have little to no fossil record, and this can be applied to much more than simply ecology. but has man y implications in chemistry and biology aswell.
ReplyDeleteAfter reading Zachos et al.'s paper, one sentence stuck with me, ""perhaps the most important developments concern the glacial history of Antartica and the scale and timing of climatic aberrations" (last paragraph p. 690). What will happen if we lose the Antartica ice sheet? Of course, sea level will rise, but how could this affect the climate and ocean systems?
ReplyDeleteAlso, would human induced global warming be considered an aberration?
The general concept seems to be that the tectonic activity would create volcanic activity, but I like that Nick also pointed out that it would have some effect on the ocean as well. Changing the currents in an ocean can change the temperatures within that ocean, which could end up having a significant effect on the organisms. I also agree with Agathe that it was very interesting that the paper pointed out that global events are not caused by just one thing and that the effects could be beneficial or harmful, it is never just one or the other.
ReplyDeleteOne of the implications of plate tectonics giving rise to mountains or mountain ranges is that it also affects precipitation patterns. This changes the ecology of flora and fauna in the area which will then influence the climate patterns for that region. Adam made a good point about the friction caused by plate tectonics resulting in gaseous upwellings, it was not the first thought that crosses my mind but would have huge ramifications on the surrounding areas.
ReplyDeleteI want to know more to the point that CHD brought up about human induced global warming becoming an aberration because I think that is something more concrete and something we can be more proactive. I thought this article did a nice job of explaining how tectonic activity could lead to ocean activity which would affect the oceanic temperature and as a result the coastal climates as well. It would be interesting what effect this tectonic activity would have on ocean currents and paths. If it lead to warming near the poles we would risk melting the glacial ice caps resulting in massive flooding and an extreme rise in water levels effectively drowning cities and leading to way less land mass available for inhabitation.
ReplyDeleteTectonic movement could influence climate conditions by creating mountains (affecting biotic to abiotic conditions in the areas), volcanism (surrounding areas abiotic and biotic are affected), and in general, the movement of the land,sea, etc.
ReplyDeleteThis provides understanding of ecological conditions in the past and present and information for conservation. I like what Sam ^ just commented about how interesting it would be to know what effect tetonic movement may have and whether it can lead to warming near poles. I think tectonics are important for predicting what can happen modernly and can provide information on what we can do to reduce warming.
In the past few years multiple news stories came out about the effects tectonic movements had on not only the climate but on the earths tilt itself, with these changes in the earths tilt in more recent times contributing to increased ice cap melting, the relevance of past studies of the earth regarding the movement of tectonics, and their effects on the earths climate, becomes ever more important to help understand and predict future climatic variation. This paper could help expand on possible future events by helping to correlate past events with future events.
ReplyDeleteThis article goes into explaining how plate tectonics can influence long-term climate change, particularly 6 changes that happened over the past 65 MYA. One way plate tectonics affects the climate would be the movement generated, causes an increase in volcanic activity. The more the plates move, the more eruptions take place, and then more CO2 is released into the atmosphere, which would generally cause global temperatures to rise. The opposite can be true where there is not much plate movement, meaning little to no volcanic eruptions and an overall decrease in average global temperature. This information could be used to help predict future temperature conditions depending on plate tectonics.
ReplyDeleteI think this a great paper and hits on science that should revolutionize the world and the way we treat the environment. If everyone in America were to read this paper and understand the science behind climate change we would see a lot of the ignorance on the subject go away and we might be able to make an impact.
ReplyDeleteTectonic Movement could affect climate condictions through the introduction of CO2 to the Atmosphere via volcanism, moving landmasses to influence oceanic currents and by moving landmasses closer or farther away from the poles. Results in this paper could be used to predict the contribution of tectonics to climate change in today's global climate and could be expanded upon by comparing the results to localized paleoclimate data on tectonic bodies. A question I have is why these large swings in relatively short periods of time were observed in the Cenozoic but not during the Mesozoic or the Paleozoic? Is it a lack of data or is it a change in tectonics or contributing factors from the Mesozoic to the Cenozoic?
ReplyDeleteThe paper discusses causation factors for the change in the Earth climate during the Cenozoic. One factor is not deemed as the cause but multiple factors and their effects are elucidated as evidence for the change. Foraminifera abundance help paleoecologist establish past Water temperatures utilizing Stable oxygen Isotopes. Plate tectonic movements does more than just raise sea levels and promote volcanism; it has causation effects on vegetation, species habitat etc. One of the factors that isn't normally contributed to climate change is the tilt of the planet. This was an interesting article to read as most usually isolate one factor but this has multiple factors.
ReplyDelete