# Chapter 2

## Global Warming and Biodiversity

Chapter 1 explained that global warming, attributable to the increase of human-caused GHG emissions, is most likely to adversely and extensively change the global environment. This chapter focuses on biodiversity, with a view to clarifying its significance in supporting human life in its role as a foundation of human life itself, while also discussing the impacts to the Earth’s biodiversity that human activities are incurring, resultant changes in ecosystems and their influence upon our way of life, with the emphasis on their relation to global warming,

## Section 1: Geological Activity and Biodiversity

Over a long history of about 4 billion years, various species have evolved on Earth by adapting to diverse environmental conditions. These diverse manifestations of life, along with inanimate factors, have interacted with the atmosphere, water and soil. These interacting natural systems, referred to as “ecosystems,” represent nets of natural elements woven together by way of their close interrelationship.

For example, most life inhale oxygen and exhale carbon dioxide. Green plants produce oxygen through photosynthesis and release it into the atmosphere. Carcasses and excreta of animals and plants are decomposed by microorganisms in the soil, and are transformed into inorganic nutrients that will be taken into plants again to be used for photosynthesis. Animals acquire energy by eating other life. Some plants benefit from insects carrying pollen for them as part of the pollination process, and others benefit from animals expanding their habitat by carrying their seeds to remote places.

Thus, there are interdependent relationships among diverse life in the Earth and the atmosphere, waters and soils; and such close relationships create diverse local ecosystems that are well-balanced. Such mutual interactions are so complicated that some of them are still not fully understood. However, it is understood that biodiversity, consisting of diverse life and their diverse ecosystems, constitute the basis of living for individual animals, plants and other organisms. This applies to human beings too, who are also part of terrestrial ecosystems. In the modern human society, people often forget their dependence on ecosystems in the biosphere, but we could not survive without respecting biodiversity in the Earth’s ecosystems. And, our human activities have influences on mutually interacted constituents of ecosystems.

### 1. Ecosystem Services

Biodiversity is not only precious in and of itself, but it is also of great value to humankind, as we gain extensive benefits from these ecosystems that are supported by diverse life.

This relationship between biodiversity and the benefits we receive from the richness of nature had not been studied systematically until 2005, when a report from the Millennium Ecosystem Assessment used the concept “ecosystem services” to explain the said relationship in an accessible way (Figure 2-1-1). The Millennium Ecosystem Assessment is a scientific work initiated by the United Nations to make global comprehensive assessments of the status of biodiversity and conservation and the sustainable use of ecosystems. The core process of the Millennium Ecosystem Assessment took four years between 2001 and 2005, and it had the participation of about 1,360 researchers and scientists from 95 countries. Findings of the Assessment explain that biodiversity constitutes the basis of ecosystem services and that the richness of ecosystem services has a strong relationship with the human well-being. Here, biodiversity is regarded as the source of all ecosystem services.

The Millennium Ecosystem Assessment report published in 2005 classifies ecosystem services into the following four categories and explains the significance of biodiversity.

## (1) Provisioning services

“Provisioning services” allow people to obtain essential resources for living, such as food, fuel, wood, fiber, biochemicals and fresh water.