Commentary on Sections Carbon budgeting Section 6: Amendment of target percentages
45.This section sets out when and how the target percentages in section 5 can be amended.
46.Subsection (1) gives the Secretary of State the power to amend the target percentage for 2020 (in section 5(1)(a), and any target percentage or percentage range set for a year after 2050 (in section 5(1)(c)).
47.Subsection (2) sets out the circumstances in which those percentages can be amended:
	paragraph (a) allows an amendment if there have been significant developments in scientific knowledge about climate change, in European Community law or policy or in international law or policy. For example, this power might be used in the event of a new international treaty on climate change;
	paragraph (b) allows an amendment if a change is made to the range of greenhouse gases covered by the target or emissions from international aviation or international shipping are added to the target.
48.Subsection (3) makes special provision on the meaning of “developments in scientific knowledge about climate change”. The first time the Secretary of State amends the target percentage for 2020, he will be able to rely on scientific developments since June 2000 to justify the change; he will not be restricted to considering only scientific developments which have taken place after the Act receives Royal Assent. If the Secretary of State wants to amend a target percentage or percentage range for a year after 2050, he will be allowed to rely only on scientific developments that occur after the percentage or range is set. When making any subsequent amendment to a target percentage or percentage range, the Secretary of State will be able to take into account scientific developments only since the percentage or range was last changed.
49.Subsection (4) allows the Secretary of State to repeal section 5(4) when he makes an order amending the target percentage for 2020. It has the effect of allowing the Secretary of State to set a target percentage for 2020 that covers all targeted greenhouse gases; section 5(4) provides that all gases other than carbon dioxide are left out of account in relation to the target percentage for 2020 – its repeal would mean that all targeted greenhouse gases count towards the target.
50.Subsection (5) prescribes that orders made under subsection (1) are subject to affirmative resolution procedure.