# 1.1 CZ Overview
## Overview
The CZ encompasses the external or near-surface Earth extending from the top of the vegetation canopy down to and including the subsurface zone of freely circulating fresh groundwater. Complex biogeochemical processes combine here to transform rock and biomass into the central component of the CZ: the soil. The CZ sustains nearly all terrestrial life, including humanity, nonetheless ever-increasing negative impacts of human society on the CZ continue.
CZ science truly is multi- and trans-disciplinary. CZ processes are represented by coupled physical, biological, and chemical processes - and an array of scientific expertise in many fields including geology, soil science, biology, ecology, geochemistry, geomorphology, hydrology, and more, is needed to understand the CZ.
## Readings and resources for this section
1. [S.L. Brantley, M.B. Goldhaber, and K.V. Ragnarsdottir. 2007. Crossing Disciplines and Scales to Understand the CZ. Elements, 3: 307–314.](https://pubs.geoscienceworld.org/msa/elements/article-abstract/3/5/307/137740/Crossing-Disciplines-and-Scales-to-Understand-the?redirectedFrom=fulltext)
2. [L. Montanarella, P. Panagos. 2015. Policy relevance of CZ Science Land Use Policy 49: 86–91](https://www.sciencedirect.com/science/article/pii/S0264837715002288?via%3Dihub)
3. [NAP. Basic Research Opportunities in Earth Science. 2001. National Academy of Sciences. Chapter 2 - CZ. ](https://nap.nationalacademies.org/read/9981/chapter/4)
4. [R.M. Lee, B. Shoshitaishvili, R.L. Wood, J. Bekker, B.W. Abbott. 2023. The meanings of the Critical Zone. Anthropocene, 42:100377](https://doi.org/10.1016/j.ancene.2023.100377)
```{admonition} Mini-Project #1
Write a one-page statement (~500 words) of four aspects of the CZ:
* define what it is;
* explain where it is;
* describe how it functions; and,
* why it is important to society.
Cite all your references in a consistent manner.
```