Ecological discourse analysis can reflect the relationship between language and other ecological phenomena, and can awaken and change people’s awareness of nature and environment. Nowadays, with the deepening dissemination of news media, news reports not only carry social functions such as transmitting information, but also constantly change people’s values and lifestyles. Appraisal Theory, which is the development of SFL account of the interpersonal, is useful to reveal the ideology hidden in the text. From the perspective of Systemic Functional Linguistics, this paper analyzes ten news reports on America pulling out of the Paris Climate Change in terms of attitude system of Appraisal Theory, aiming to reveal Western mainstream media’s ideology of climate change and environment. Thus, the paper proves the operability and practicability of Appraisal Theory in ecological discourse analysis, especially in the revealing of ideology, calling for establishing an appropriate and beneficial ecosophy. Through the analysis, it can be found that the reporters of The Guardian have ecological awareness to some extent, and that they express concern about climate change, recognizing that climate change is mainly caused by improper human behavior, and advocating that the world should work together to cope with the ecological crisis. However, they overemphasize the value of human beings, and ignore other forms of life. Eco-linguists should pay attention to the ecological discourse, encouraging those discourses that are conducive to the harmonious development of ecology, and restrict those discourses that are not harmonious with ecology so as not to affect the public’s value judgments.