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Monsoons of Asia caused Greenhouse to Icehouse Cooling

Periodic Reporting for period 4 - MAGIC (Monsoons of Asia caused Greenhouse to Icehouse Cooling)

Reporting period: 2020-03-01 to 2021-02-28

What is the problem/issue being addressed?
Asian climate and monsoons are genetically linked to high orography associated with the India-Asia collision starting ca. 60 Myrs ago. However, the relation between Greenhouse to Icehouse cooling and Asian atmospheric patterns remains to be explored. It depends on major changes of the past geographic configuration of Asia that remain highly controversial. The timing of the India-Asia collision, the uplift of the Himalaya-Tibetan orogen and the disappearance of the immense sea that use to stretch over Eurasia.

Why is it important for society?
Asian climate and monsoons govern the life of billions of people and the rich biodiversity Asia. Asian climate and monsoons have been shaped and modulated by a wide range factors including mountain uplift, pCO2 level, vegetation and land sea distribution. How increasing pCO2 levels and global temperatures will affect Asian climate and monsoons in the future must be addressed by exploring past greenhouse times with comparable conditions in order to validate model reliability and predictions.

What are the overall objectives?
Long term climate records ultimately enable to understand regional to global feedback mechanisms between climate, geodynamic, paleogeography, surface processes and biotic evolution In this project we aimed to understand the mechanisms that are and have been controlling Asian climate and monsoons since over 50 million years ago.

Conclusions of the action
The objectives of the action have been achieved and led to unexpected discoveries. We explored and dated all targeted records revealing past geographic configurations and environmental conditions in various parts of Asia. To these records, novel climate proxies were applied and developed within the MAGIC project. These proxy records and boundary conditions were integrated into climate model simulations to test hypotheses on the drivers of past Asian climate and biotic changes.
We discovered that past geographic configurations and were surprisingly different than previously accepted. Our results redefined (1) the position of tectonic plates during the India-Asia collision, (2) the timing of the uplift of various parts of the Tibetan plateau, (3) the fluctuations of the shallow sea that used to cover Eurasia and (4) the expansion of deserts in Central Asia. These new geographic boundary conditions have important implications on geodynamic, climate and biotic models that have been explored.
WORK PERFORMED AND MAIN RESULTS
The project has been set up as 3 main objectives overlapping in time:

Objective A. Three PhDs date and describe each sedimentary environmental record from NE Tibet (China), SE Asia (Myanmar) and the Paratethys region (Western China and Tajikistan).
Objective B. Postdocs apply and develop various environmental proxies to these sedimentary records with the goal to characterise environmental changes.
Objective C. An integrative climate modeler integrates dated proxy records to constrain simulations.

Objective A on stratigraphy has been fully completed. We have been able to access, sample and date the three targeted records.
Objective B on proxies has been fully completed. The work included exciting cross-calibration of multi-proxy tools developed within MAGIC.
Objective C on climate modeling has been completed. It has finally been carried out by 2 PhDs. One in the ERC and one in collaboration.
General circulation models have been coupled with vegetation models validated by vegetation and climate proxy data obtained in the project.
However, we have not been able to run carbon cycle models in the scheme of the project and remains to be done in the aftermath of the project in collaboration.

OVERVIEW OF THE RESULTS
- The discovery that Myanmar used to be at the equator enabled the reconstruction in time and space of the controversial India-Asia collision and opened a new pathway to understand Asian biotic evolution.
- The precise chronology of the uplift of the Tibetan plateau since 40 Myrs ago enables to understand the role of the plateau on surface, atmospheric and biotic processes.
- The complete record of the birth, fluctuations and retreat of the former Eurasian epicontinental sea and the discovery of its major role as a carbon sink on global climate during greenhouse conditions is has implication for understanding current climate change and its mitigation.
- The precise record of the onset of loess-like dust generation in Central Asia 40 Myrs ago and its evolution and the role of dust in the greenhouse to icehouse climate transition.
- The precise temperature shift associated with the greenhouse to icehouse transition using a newly developed proxy helps understand monsoons and westerly moisture under climate change.
- The drivers of a very peculiar of Asian monsoons in a greenhouse world with Asia being very arid was revealed by climate models integrating proxy records enable to better understand monsoons in high CO2 world.
- The complete record of steppe-desert biome and the driving mechanisms of its collapse 34 Myrs ago and recovery 15 Myrs ago showing its fragility under climate change.

EXPLOITATION AND DISSEMINATION
The discoveries described above have been published in top scientific journals and made available to the public by multiple medias.
The participation at international meetings presenting respective results has started to establish the MAGIC team as a major player in the field.
Over 40 publications in scientific journals so far including Science and Nature journals.
Our results and methods have been included in classes to university students as well as secondary school programs.
Our results have been disseminated to various outreach media to the general public (dedicated website, newspaper, TV shows, Youtube, Twitter, etc...).
New proxies developed in the project have been disseminated to the scientific community through meeting and publications.
An important spinoff of the project has been the development of past geographies and tools to create them with a related database.
These enable to convey our results and methods to the scientific community but also outreach to the general public.
These are disseminated through publication and meetings but also a dedicated interactive website and an open source software (see below).
These tools are for the use of climate modellers as well as broader Earth and Life Science applications and for teaching university, secondary school classes, and the general public where they have raised broader interest.
The MAGIC project has been rich in unexpected results and progress beyond the state of the art with the development of new methods across disciplines from Geology towards Biology with the help of the close collaboration in the project of the geologists, modellers, ecologists and biologists

Of the major results described in the overview of the results above, a large part were unexpected.
A highlight of this project is the contribution to the development and combinations of novel proxy approaches combined to numerical simulations for their validation. The resulting techniques are very promising to interpret biotic as well as environmental variations and in particular past elevations, moisture and seasonal conditions. Such a broad transdisciplinary integration was made possible by the large scale of the ERC and pave the way for future research in our fields.
MAGIC Team Workshop in Potsdam
Fieldwork pictures from the 3 targeted areas of MAGIC