What Does Global Land Climate Look Like at 2°C Warming?

Constraining an increase in global mean temperature below 2°C compared to pre‐industrial levels is critical to limiting dangerous and cascading impacts of anthropogenic climate change. Understanding future climatic changes and their spatial heterogeneity at 2°C warming is thus important for policy makers to prepare actionable adaptation and mitigation plans by identifying where and to what extent lives and livelihoods will be impacted. This study uses the recently released NASA Earth eXchange Global Daily Downscaled Projections (NEX‐GDDP) CMIP6 data to provide a broad overview of projected changes in six key climate variables and two climate impact indicators at a time when warming exceeds 2°C. Analysis of global mean temperature changes indicates the 2040s as the decade when most CMIP6 models reach 2°C warming with respect to a pre‐industrial period (1850–1900). During the 2040s, we find that global mean temperature, precipitation, relative humidity, downwelling shortwave and longwave radiation, and wind speed over land under the high emission scenario are projected to change by +2.8°C, +22.4 mm/year, −0.73%, −2.23 , +15.9 W/m2, and −0.04 m/s, respectively. Many of the future changes are expected to exacerbate climate impacts including heat stress and fire danger. Our analysis shows geographic patterns of policy‐relevant climatic changes, as parts of the globe will experience significant climate impacts even if the goal to keep warming below 2°C goal is achieved. Our results highlight the urgent need for further studies focused on identifying key hotspots and advancing region‐specific actionable adaptation and mitigation plans. Plain Language Summary: Robust understanding of the spatial patterns of climatic change as the world approaches 2°C warming is a priority for policy makers preparing actionable adaptation and mitigation plans. The recently released NASA Earth eXchange Global Daily Downscaled Projections (NEX‐GDDP) data is a unique tool for assessing these changes with unbiased projections at 16‐64 times finer spatial scale than the ones originally available. Our work uses the NEX‐GDDP data to answer a simple but important question, "What does global land climate look like at 2°C warming?" We find that the Earth will likely reach 2°C of global warming by the 2040s. In the 2040s, our analysis shows significant changes in six key climate variables (mean air temperature, precipitation, relative humidity, downwelling shortwave and longwave radiation, and wind speed) but with geographically varying magnitude and direction of changes. These changes collectively result in increasing risks of heat stress and fire which already manifest as life‐threatening impacts resulting from climate change. Many of the projected changes are expected to exacerbate climate impacts, and our fine scale spatial analysis reveals that parts of the globe (e.g., countries in lower latitude) will experience significant climate impacts even if pledges to limit warming to less than 2°C are achieved. This study provides a comprehensive assessment of projected climate changes under 2°C warming and highlights the urgent need for further studies focused on identifying key hotspots and advancing region‐specific actionable adaptation and mitigation plans. Key Points: CMIP6 models show that the Earth likely will reach 2°C of global warming by the 2040s without significant policy changesGeographic pattern of changes in key climate indicators portend unfavorable conditions of habitability for large populationsDownscaled climate projections provide finer scale spatial patterns that enable region‐specific climate adaptation and mitigation strategies [ABSTRACT FROM AUTHOR]