What are the limitations of this method of reconstructing climate? Lab 2 EVR 41

Question

What are the limitations of this method of reconstructing climate? Lab 2 EVR 41 14 Climate Change Palynology is the study of usi Summer 2018 Palynology Assignment ing the changing assemblages of pollen from certain species which have specific climatic tolerances to reconstruct past climates for certain regions Researchers measure the amount of pollen that comes from a certain species parameters in which they prefer to grow. They then assume that if high abundances of that species are present sometime in the past that the climate of that region was similar to that where the species currently grows. This is called the transfer function. and the climate The central North Island of New Zealand has experienced a large climate shift over the last 15,000 years. To reconstruct the change in climate over that period for this region, the palynologists extracted cores from bogs across the region, dated their stratigraphy and collected pollen from those cores. They were interested in the difference between the climates of two span shots in time reconstructed by the natural vegetation: 800 years BP and 15,000 years BP. The 800 years ago portions of the cores were used as a time period of "modern" natural vegetation Four species of plants were used because of their known climate tolerances: 1. Rimu - maximum growth at average temperatures of 15 °C and average annual 2. Beech - maximum growth at average temperatures of 7°C and average annual 3. Tree Ferns - maximum growth at average temperatures of 15 C and average annual 4. precipitation of 1300 mm precipitation of 750 mm precipitation of 1350 mnm Herbs-maximum growth at average temperatures of6 °C ani average annual precipitation of 800 mm This region of NZ is very close to the Central North Island Volcanic Plateau which has volcanoes that have erupted intermittently over the last 20,000 years. The tephra ejected from these eruptions has spread over hundreds of miles and contributed to the rich soils of this region.

Explanation / Answer

Limitation of paleo climatologist of reconstructing climate are

1) , past changes in climate are unlikely to have been caused by increasing GHG concentrations. Different boundary condition mean that we cannot be confident that the characteristics of a warmer GHG induced future climate will resemble those of a past climate which was also warmer.

--- largely disagreed that value data is not applicable. Former form intervals represent partial analogues as to how physical and biological systems respond. An example would be the impact of permafrost warming on permafrost we are not so much concerned about the driver of change rather the impact that this change will have.

--- the things that are changing a temperature and precipitation patterns themselves. Those are what are driving changes. Need an example of what co2 bill due to global circulation. It is probably true that CO2 girls will have unknown influence on tree ring growth.

2) there may be large uncertainty in the dating of material used to draw timelines for paleo records.

-- we accept that uncertainty exist however we know the main source and are moving to quantify the effects of the error uncertainty and other uncertainty exist as well. All sources of variance need to be addressed.

3) paleo reconstruction are generally not geographically comprehensive

--- all records suffer from Geographic problems.

---- agreed you can never have too much data. however at a certain level it is quite conceivable to make regional to Continental scale synthesis. Synthesis and network analysis are relatively new and not easily discoverable and effort is needed to make the data available. However it should be done and should be made more obvious to users.

4) only mean temperature and precipitation information is available does limiting the use of these data in climate change scenarios.

--- we agree there is a need to produce Ultra high resolution. However mean temperature and precipitation of the primary control of ecosystem development and are therefore key variables.

5) the older the paleoclimate information the less confidence there is in its reliability and the less there are available.

--- the problem is that high resolution can be available but less generally available because it is less preserved and harder to find.

* paleoclimate reconstruction technique that will help validate the finding of study regarding reconstruction both temperature and precipitation is that paleoclimate studies using stalagmite were focused on paleotemperature reconstruction overtime. The functionality of speleothems as Delhi temperature records is founded on two relationships : the temperature dependence of oxygen isotopic composition of meteoric precipitation and the temperature dependence oxygen isotopic fractionation that accompanies mineral crystallization. Because the climate of deep poorly ventilated caves remain steady throughout the year at approximately mean annual temperature, and because the drip water often reach thermal equilibrium with their surrounding during infiltration into deep Caves. How about the magnitude and direction of the slope linking meteoric precipitation with temperature introduces a large degree of uncertainty into this relationship both spatially and temporally.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.