In 2018, the United Nations’ Intergovernmental Panel on Climate Change, a collection of the world’s leading climate scientists, issued a landmark report that took stock of the differences in impacts between a 1.5°C global warming limit and a 2°C limit—in other words, what would happen if we avert a half degree in the rise of average temperatures. The report also contained global CO₂ emission budgets for meeting these thresholds and their probabilities.

The panel found that limiting the rise to 1.5°C could stave off dramatic escalations in the impacts of climate change (see sidebar for examples).

The IPCC has stated that the global carbon budget, or the total amount of CO₂ that can be released into the atmosphere while maintaining a 67% probability of limiting warming to 1.5°C, is (as of Jan. 1, 2020) about 340 GtCO₂. To meet this budget, we have to reduce global CO₂ emissions by 65% by 2030 and completely phase out CO₂ emissions by 2040.

The good news is, if we act quickly and responsibly, we can stay within the 1.5°C budget. We have all the tools, policies, strategies, products, and affordable renewable energy needed to do so as outlined in the International Energy Agency’s “World Energy Outlook 2020,” which tracks energy production and consumption worldwide. Such strategies are also available in the recorded sessions from the CarbonPositive Reset! 1.5°C Global Teach-In, Architecture 2030’s three-day virtual event, which saw thousands of professionals—including architects, planners, engineers, educators, developers, manufacturers, and policymakers—from around the world participate. Ample evidence, actions, and proven strategies from the Teach-In illustrate the feasibility of meeting the 1.5°C budget.

source: Architecture 2030 and IPCC SR15, Table 2.2

Today, many governments, industries, businesses, organizations, and even U.N. affiliates are still using outdated targets and timelines—many times unintentionally. This must stop. Erroneous claims of meeting the 1.5°C budget only ensure that the world will fail to avert the worst effects of climate change.

How do we rectify this? The U.N.’s Framework Convention on Climate Change must update and publicly post the 1.5°C carbon budget annually and revise targets and dates when appropriate. Architecture 2030 has sent an open letter to the UNFCCC Secretariat urging it to do so, and we encourage all organizations to do the same. By working together to meet the IPCC’s 1.5°C global carbon budget, we can prevent the escalating impacts of climate change.

Learning how to design, plan, and build for a 1.5°C carbon budget and world is critical. To see the recorded sessions from the Architecture 2030 Teach-In that occurred this past September, visit