Climate Science

Climate change refers to a change in weather patterns over a long period of time. A defining characteristic of climate change is an increase in the global average air temperature, termed global warming. The climate change that we are experiencing today is occurring at a rate unprecedented in geological history, and scientists are virtually certain that it has been caused by human activity (primarily the burning of fossil fuels and land use). This is evident in the correlation between atmospheric carbon dioxide concentrations (currently at the highest level experienced in millions of years) and global average temperature. This change in our atmospheric composition has and will affect the climate in different parts of the world differently. Extreme temperatures and precipitation; weather events such as floods, droughts, wildfires, and hurricanes; sea level rise, ocean acidification, and biodiversity loss are observed changes that are projected to continue and intensify for centuries to come. The degree to which these changes occur is now up to us.

Provincial Projections

National Projections

Canadian Centre for Climate Services

ClimAtlantic – Climate Resources for Atlantic Canada

Climate Central – Sea Level Rise Maps

Our World in Data

The Intergovernmental Panel on Climate Change (IPCC) is the United Nations body for assessing the science related to climate change. They provide policymakers with knowledge and guidance regarding climate change projections, implications and potential future risks, as well as adaptation and mitigation options. The 6^th assessment reports released in 2021-22 are the most recent and extensive climate analyses.

The United Nations Framework Convention of Climate Change (UNFCCC or UN Climate Change)  is the entity tasked with supporting the response to the threat of climate change, based on the IPCC scientific assessments. The UNFCCC is the parent treaty of the Paris Agreement of 2015 and the Kyoto Protocol of 1997. The objective of each of these global agreements is to “stabilize greenhouse gas (GHG) concentrations in the atmosphere at a level that will prevent dangerous human interference with the climate system, in a time frame which allows ecosystems to adapt naturally and enables sustainable development”. 

The IPCC released a special report in October 2018 titled “Global Warming of 1.5°C”. This report described how a 1.5°C increase in global average temperature above pre-industrial levels is considered a critical threshold beyond which the impacts of climate change on ecosystems and society will be far more significant. The report explains how a jump from 1.5°C to 2°C may be the difference between the ability and inability for society to adapt. AR6 estimates that human activities have already increased global average temperature by 0.8°C to 1.3°C above pre-industrial levels (1850-1900).

Global Climate Science Reports – IPCC

United Nations Framework Convention on Climate Change

In the first Report of AR6 (The Physical Science Basis of Climate Change) released in August 2021, it is stated that 1.5°C of warming will be exceeded within the next 20 years under all emissions scenarios – even if emissions drop to zero today, enough greenhouse gases exist in the atmosphere, that we cannot avoid this increase. 2°C of warming will likely be exceeded by mid-century if deep emissions reductions do not occur.

Even at 1.5°C, there will be an increasing occurrence of extreme weather events unprecedented in the observational record – such events have already begun to be observed. Changes in and likelihood of extremes increase with each additional increment of warming – every fraction of a degree matters. If emission levels continue unchecked, global warming could approach or surpass 5°C by 2081-2100, creating a world that we cannot fathom. However, if emissions are dramatically and quickly reduced (the lowest emission scenario modelled), the global surface temperature may decline back to below 1.5°C toward the end of the 21^st century. The direct relationship between emissions and temperature is the key take-away of this AR6 report – our actions matter now more than ever.

Part 2 of AR6 released in February 2022 covers Impacts, Adaptation and Vulnerability. This World Resources Institute article pulls the following key findings:

1. Climate impacts are already more widespread and severe than expected.
2. We are locked into even worse impacts from climate change in the near-term.
3. Risks will escalate quickly with higher temperatures, often causing irreversible impacts of climate change.
4. Inequity, conflict and development challenges heighten vulnerability to climate risks.
5. Adaptation is crucial. Feasible solutions already exist, but more support must reach vulnerable communities.
6. But some impacts of climate change are already too severe to adapt to. The world needs urgent action now to address losses and damages.

A list of takeaways was similarly developed for Part 3 of AR6, Mitigation of Climate Change, which came out in April 2022:

1. Global GHG emissions have continued to rise, but in pathways that limit warming to 1.5 degrees C, they peak before 2025.
2. There’s no room for building new fossil fuel infrastructure.
3. We need rapid transformations across all systems to avoid the worst climate impacts.
4. Changes in lifestyle and behaviours have a significant role to play in mitigating climate change.
5. Limiting global temperature rise to 1.5 degrees C will be impossible without carbon removal.
6. Climate finance for mitigation must be 3 to 6 times higher by 2030 to limit warming to below 2 degrees C.

Each of these reports are extensive and technical, but a Synthesis Report was released in March 2023 that summarizes and integrates all material into a short and accessible format.

This information must guide our every action. We must peak emissions by 2025, halve them by 2030, and reach net-zero by 2050.