Canada created its first constitutional document in 1867, known as the British North American Act or more simply, the Constitution Act, 1867. This original document set out some of the founding principles of Canadian legislation and began dividing powers and responsibilities between the federal government and the provincial governments. This division of powers is called federalism.
Federalism means that legislative sovereignty (or power) is divided between a national legislature or Parliament (the federal government) and provincial legislatures.
As more and more provinces joined Canada, they created their own laws and regulations in accordance with their designated powers.
The respective federal and provincial powers are set out in Sections 91 & 92 of the Constitution Act, 1867.
For reference we have listed some of them below:
10. Navigation and Shipping;
12. Sea Coast and Inland Fisheries;
24. Indians, and Lands reserved for the Indians;
27. The Criminal law.
5. The Management and Sale of the Public Lands belonging to the Province and of the Timber and Wood thereon;
13. Property and Civil Rights in the Province;
16. Generally all Matters of a merely local or private Nature in the Province.
In 1867, the environment wasn’t much of a consideration and certainly did not play a significant role in the drafting of the Canadian Constitution. However, the heads of power listed above do have some relationship with the environment.
Since the Constitution Act, 1867, does not specify whether the federal or provincial governments are responsible for legislating the environment, how do the federal and provincial governments divide up the responsibility of environmental law?
This is an important and difficult question that often arises when trying to create high quality and effective environmental laws and there are a few legal concepts that you will want to understand in order to appreciate how complicated it can get.
The doctrine of paramountcy is the idea that although federal and provincial powers are generally meant to be divided up, in the event that they do come into conflict, federal powers will win. This has significant importance in environmental law because of the lack of clarity regarding which level of government is actually in charge. Notably, this is a limited idea and provincial and federal statutes may both govern similar areas of the law, so long as the fundamental purpose of the federal law is not affected.
The Constitution Act, 1867, along with some guidance from constitutional principles, gives legislatures the power and guidance to draft environmental legislation across the country.
 Constitution Act, 1867 (UK), 30 & 31 Vict, c 3, reprinted in RSC 1985, App II, No 5, s 91.
 Neil Craik et al, Public Law, 2d ed (Toronto: Emond Montgomery, 2011) at 81.
 Constitution Act, 1867, s 91.
 Constitution Act, 1867, , s 92.
 Neil Craik, at 80.
 Constitution Act, 1867, s 92(A)(3).
 Canadian Western Bank v Alberta, 2007 SCC 22, para 124.
 Canadian Western Bank v Alberta, 2007 SCC 22, paras 32-33.
 Hodge v R,  UKPC 59,  9 AC 117.