Table 1 Marginal values of carbon stored by additional species to a grassland ecosystem for three carbon prices capturing the range summarized by the Interagency Working Group on the Social Cost of Carbon (25).

Values are means and 95% confidence intervals in $ sp−1 ha−1 for ecosystem carbon (soil and plants) averaged across the BigBIO and BioCon grassland experiments. Values are in 2010 U.S. dollar (USD).

Number of speciesMedium estimate
of social cost of
C ($137.26 MT C−1)
Low estimate
of social cost of
C ($41.94 MT C−1)
High estimate
of social cost of
C ($400.33 MT C−1)
2$804.55 ($524.3–$1059.54)$245.83 ($160.2–$323.74)$2346.54 ($1529.16–$3090.24)
3$333.38 ($201.36–$473.06)$101.87 ($61.52–$144.54)$972.33 ($587.27–$1379.72)
4$183.05 ($107.8–$268.18)$55.93 ($32.94–$81.94)$533.89 ($314.41–$782.17)
5$115.83 ($67.21–$174.15)$35.39 ($20.54–$53.21)$337.84 ($196.03–$507.94)
6$79.94 ($45.83–$123.40)$24.43 ($14.00–$37.71)$233.15 ($133.66–$359.91)
7$58.50 ($33.19–$91.64)$17.88 ($10.14–$28.00)$170.63 ($96.81–$267.26)
8$44.68 ($25.15–$70.43)$13.65 ($7.68–$21.52)$130.31 ($73.35–$205.43)
9$35.24 ($19.71–$56.20)$10.77 ($6.02–$17.17)$102.77 ($57.50–$163.90)
10$28.51 ($15.87–$45.89)$8.71 ($4.85–$14.02)$83.14 ($46.29–$133.83)
11$23.54 ($13.05–$38.06)$7.19 ($3.99–$11.63)$68.64 ($38.06–$111.00)
12$19.76 ($10.92–$32.08)$6.04 ($3.34–$9.80)$57.63 ($31.85–$93.56)
13$16.83 ($9.27–$27.41)$5.14 ($2.83–$8.37)$49.08 ($27.04–$79.93)
14$14.50 ($7.97–$23.68)$4.43 ($2.44–$7.24)$42.30 ($23.25–$69.08)
15$12.63 ($6.93–$20.67)$3.86 ($2.12–$6.32)$36.83 ($20.20–$60.30)
16$11.10 ($6.07–$18.20)$3.39 ($1.86–$5.56)$32.36 ($17.72–$53.09)