## 2 Ecological Footprint and Levels of Ecological Consumption
Data source: National Footprint Account results (2019 Edition) from the Global Footprint Network (GFN). As the most influential countries, the G20 countries are used as examples to illustrate national ecological consumption. Table 1 lists the EF values and \"number of Earths\" of the G20 countries from 1990 to 2016 (\"number of Earths\" is the ratio of national EF to globally available BIO, which means that, if the level of ecological consumption of one certain country is universal, this is how many Earths would be needed to support humanity to be ecologically sustainable). For the time period 1990-2016, only the EF values of India were lower than the globally available BIO, and India was the only country with an ecological surplus; China and Indonesia transformed from countries with an ecological surplus into countries with an ecological deficit; the EF values of the United States and Canada were extremely large. In 2000, the EF value of the United States was even higher than 10 gha per capita and 5.52 Earths were needed to support the lifestyle of the United States. It is encouraging to find that the EF values of four developed countries (France, Germany, Japan, and the United Kingdom) show downward trends. The EF values of Germany decreased by the largest \begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & \multicolumn{2}{c}{**1990**} & \multicolumn{2}{c}{**2000**} & \multicolumn{2}{c}{**2010**} & \multicolumn{2}{c}{**2016**} \\ \cline{2-10}  & **EF** & **Earths** & **EF** & **Earths** & **EF** & **Earths** & **EF** & **Earths** \\ \hline Argentina & 3.07 & 1.49 & 3.13 & 1.69 & 3.25 & 1.91 & 3.37 & 2.06 \\ Australia & 8.04 & 3.88 & 8.06 & 4.33 & 8.32 & 4.89 & 6.64 & 4.07 \\ Brazil & 2.89 & 1.40 & 3.08 & 1.66 & 3.00 & 1.76 & 2.81 & 1.73 \\ Canada & 8.94 & 4.32 & 9.10 & 4.90 & 8.34 & 4.90 & 7.74 & 4.75 \\ China & 1.53 & 0.74 & 1.92 & 1.03 & 3.36 & 1.98 & 3.62 & 2.22 \\ France & 5.59 & 2.70 & 5.54 & 2.98 & 5.25 & 3.09 & 4.45 & 2.73 \\ Germany & 6.90 & 3.34 & 5.51 & 2.96 & 5.39 & 3.17 & 4.84 & 2.97 \\ India & 0.78 & 0.38 & 0.86 & 0.46 & 1.07 & 0.63 & 1.17 & 0.72 \\ Indonesia & 1.20 & 0.58 & 1.35 & 0.73 & 1.51 & 0.89 & 1.69 & 1.04 \\ Italy & 5.18 & 2.51 & 5.60 & 3.01 & 5.29 & 3.11 & 4.44 & 2.72 \\ Japan & 5.46 & 2.64 & 5.29 & 2.84 & 4.69 & 2.76 & 4.49 & 2.76 \\ Republic of Korea & 3.74 & 1.81 & 5.06 & 2.72 & 5.88 & 3.46 & 6.00 & 3.68 \\ Mexico & 2.50 & 1.21 & 2.85 & 1.53 & 3.18 & 1.87 & 2.60 & 1.60 \\ Russia & 6.90 & 3.34 & 4.69 & 2.52 & 5.35 & 3.15 & 5.16 & 3.17 \\ Saudi Arabia & 2.13 & 1.03 & 3.77 & 2.03 & 5.66 & 3.33 & 6.23 & 3.83 \\ South Africa & 3.36 & 1.62 & 3.05 & 1.64 & 3.60 & 2.12 & 3.15 & 1.93 \\ Turkey & 2.58 & 1.25 & 2.92 & 1.57 & 3.21 & 1.89 & 3.36 & 2.06 \\ United Kingdom & 5.84 & 2.82 & 5.73 & 3.08 & 5.31 & 3.12 & 4.37 & 2.68 \\ United States & 9.87 & 4.77 & 10.25 & 5.52 & 8.94 & 5.26 & 8.10 & 4.97 \\ \hline \end{tabular} Notes: The EF value of Russia of 1990 is not available and the data in the row is of the year 1992.  
\end{table} 
Table 1: Ecological footprint (EF) values and “number of Earths” of G20 countries for the time period 1990–2016. Figure 2: Evolution of “number of Earths” needed (1961–2016). Data source: National Footprint Account results (2019 Edition) from the GFN. extent (29.84%). In 2016, the EF value of Germany was about 40% lower than the EF of the United States. The EF values of seven countries (Argentina, China, India, Indonesia, Turkey, Republic of Korea, and Saudi Arabia) show upward trends. The EF values of Republic of Korea, China, and Saudi Arabia increased by 60.63%, 136.72%, and 193.10%, respectively.