Ministry of the Environment, Conservation and Parks

Responsibilities

Air quality

The MECP works to improve air quality through legislation, targeted programs, and partnership agreements with other neighbouring airsheds. This includes using a network of air quality stations that provide real-time air pollution data. The ministry communicates air quality to the public by providing an Air Quality Index based on ambient levels of ozone, fine particulate matter, nitrogen dioxide, carbon monoxide, sulphur dioxide, and total reduced sulphur compounds.

Brownfields

MECP is responsible for administering Ontario Regulation 153/04 which requires, under specific circumstances, a Record of Site Condition (RSC) to be submitted to the Ministry for acknowledgement. A RSC contains Environmental Site Assessments that ascertain the current condition of a site, including whether contamination exists on-site. The RSC is required when a property owner is choosing to change the property use from a less-sensitive to more-sensitive use (Example: Industrial Use to Residential Use) and is often required by the municipality's Chief Building Official before approval of a building permit.

Climate change

The ministry released a climate change action plan in 2007, setting greenhouse gas reduction targets for the province. It is the aim of the provincial government to reduce its emissions to:

• 6% below 1990 levels by 2014;
• 15% below 1990 levels by 2020; and
• 80% below 1990 levels by 2050.

The ministry released an update on its progress towards these targets in 2014, indicating that it had surpassed its 2014 target. It also indicated that current trends and policies would result in 170 megatonnes of emissions, or 69% of its 2020 target.

In 2011, the ministry published Climate Ready, its first climate change adaptation strategy and action plan for 2011 to 2014. The report acknowledges that Ontario has experienced a 1.4°C increase in average temperatures, and that the province is suffering from more frequent extreme weather events including prolonged heat waves, torrential rain and wind storms, and drought. The report outlines how the province should prepare for and minimize the negative impacts of a changing climate, as well as strategies to reduce greenhouse gas emissions.

Under Ontario Regulation 452/09, any facility in Ontario that emits more than 25,000 tonnes of greenhouse gases annually is required to report their emissions. The reports must be verified by an accredited third party, to ensure it meets the requirements of ISO 14064-3. Reports are then submitted through Environment Canada's single window system.

A cap and trade program was implemented on January 1, 2017, which projected to cost the average Ontario household about $13 more per month to fuel a car and heat a home in 2017. By 2017 year end, the cap and trade program brought in nearly $2 billion in revenue. After Progressive Conservative Premier Doug Ford was sworn into office on June 29, 2018, he revoked Ontario's cap and trade program on July 3, 2018.

Drinking water

Ontario municipalities have responsibility for building and maintaining drinking water systems, but the ministry regulates these systems to achieve acceptable standards in water quality and safety.

Ontario Parks

Since its integration into the Ministry of the Environment, Conservation and Parks (MECP), Ontario Parks has become part of a broader provincial mandate focused on environmental protection, conservation, and climate resilience. The agency continues to manage over 340 provincial parks and conservation reserves, now under MECP's oversight, which emphasizes ecological integrity, biodiversity, and sustainable recreation. In recent years, Ontario Parks has seen significant expansions, including the addition of 19 protected areas in 2025, and a historic investment of nearly $60 million to build and upgrade over 1,000 campsites across the province, marking the largest expansion in 50 years. The ministry replaced the Class Environmental Assessment process with a streamlined Project Evaluation Policy to better align with MECP's regulatory framework. Ontario Parks operates under a Special Purpose Account and is guided by the Ontario Parks Board of Directors, which advises on strategic planning and long-term conservation goals.

Ontario Provincial Conservation Authority

In October 2025, the Ontario government created the Ontario Provincial Conservation Authority to oversee the 36 conservation authorities in the province, and to merge them into seven, through the Conservation Authorities Act. After public consultation, this number increased to nine in March 2026, with implementation to take place in May.

Other

• Environmental assessments
• Environmental approvals
• Environmental registry
• Environment maps
• Great Lakes and Watersheds
• Pesticides

List of ministers