However, it is those of us who are paid to make the decisions to develop, improve and enforce environmental standards, I submit，who must lead the change.

【翻译】然而，我提议，正是我们这些制定发展、改进和执行环境标准决策而得到回报者，才必须领导这一变革。

【分析】I submit 是插入语，为分析方便暂去掉。

这样，第一个who 从句是定语从句；第二个who 从句，引导了“分裂句”中的其余部分，可换用that。

However, it is those of us who are paid to make the decisions to develop, improve and enforce environmental standards （定语从句）that must lead the change.