Climate model trends over different time windows

This could be one of the most important papers to be published since James Hansen’s Pipeline paper a year ago. Climate change will continue to get worse for centuries after net-zero is achieved. It had been assumed that net-zero would halt further temperature rise and with it climate impacts, since the relationship between CO2 loading and temperature was thought to be near-linear. The models used to support the IPCC 1.5 special report were based on transient climate states, assumed scenarios and time sampling. They looked at global averages rather than regional effects and stop at 2100. Critically they tended also not to include triggered tipping points. The new paper from Andrew King et al from University of Melbourne but with co-authors from Reading, Seoul and 4 other Australian centres, ran coupled climate models for 1000 years into the future with different net-zero achievement points from 2030 to 2060. SSP5-8.5 was used up to the net-zero point to simplify the experiment but also to clearly illustrate the criticality of reaching net-zero as soon as possible, with as low a starting temperature as possible. In all cases mean surface temperature continued to rise after net-zero, but the later net-zero was achieved, the higher the temperature at the start, the faster the continued rise. All showed considerable slowdown of rise rate, but not uniformity or overall stability. Regional climate change continued, especially in the southern hemisphere with Australia continuing to rise by a further +1C if net-zero is delayed to 2060. The Southern Ocean temperature would also continue to rise significantly with continued reduction in Antarctic Sea Ice. This combination would likely lead to the continued melting of the West Antarctic Ice Shelf. Meanwhile the Arctic sea-ice would stabilise but likely see years of ice-free summer conditions. Rainfall patterns and ENSO change during stabilisation. Weather extremes are locked in, but the relative difference in levels greatly increases with net-zero delay. Even a 5 year delay still has influence 1,000 years into the future. The key takeaway for me is the graph below. Things may continue to get slowly worse even after net-zero, but the point at which it is achieved is critical. We can’t get back to the climate of my youth, but we can control how bad it gets for people born today. The faster we decarbonise, the least bad the future will be, for humanity and nature alike. Story: https://lnkd.in/ev5QK5bg Paper: https://lnkd.in/eaKkeHN7 #climatechange #netzero

New paper alert! A fully coupled climate reanalysis by Vince Cooper covering 1850-2023. We used strongly coupled data assimilation on observations of sea surface temperature, land-based air temperature, sea-level pressure over the ocean, and satellite sea-ice concentration at monthly resolution. As far as we know, this is the first time that these fields have been simultaneously reconstructed over the historical period. Results show significant low-frequency variance in ENSO, with a peak near the start of the 20th century, muted modern cooling trends in Southern Ocean SST (see figure below), a decline in Arctic sea-ice area since the 19th century, and relatively small changes in Antarctic sea-ice area. Additional key points: * Most reanalysis datasets consider each component of the climate system independently (i.e., separate atmospheric and oceanic reanalyses), leading to inconsistencies in coupled variability. Here, we use strongly coupled data assimilation, which means that all observations update every component of the climate system. * Efficient emulators are used to propagate the memory of past observations forward in time. We use cyclostationary linear inverse models trained on 8 CMIP6 model simulations to include the role of model error in the reconstructions. These models are used to create 8 separate reanalyses, propagating the full error covariance matrix for all climate variables. * A 1600-member ensemble is created by sampling the posterior distributions in a dynamically consistent process, providing a large sample of equally likely reanalyses of historical climate. This provides a rich dataset for exploring climate variability with uncertainty quantification. The preprint can be found here: https://lnkd.in/gbEtR4Jw

🌡️ Climate Shift in Action: Minimum Temperature Trends under SSP585 🌍 This ridge plot visualizes the evolution of minimum temperatures across time — comparing observed records (1981–2024) with CMIP6 climate projections under the SSP585 high-emission scenario. 🔍 What the plot reveals: 📉 The observed distribution shows a bimodal structure — with significant density in the moderate temperature range. 📈 As we move through future periods (2015–2042, 2043–2073, 2074–2099), there’s a clear rightward shift, indicating increasing minimum temperatures. 🔥 By the late 21st century (2074–2099), higher minimum temperatures dominate, suggesting persistent warming even at night, with important implications for agriculture, human health, and ecosystems. 📊 Why this matters: Minimum temperatures are rising faster in many regions than maximums — contributing to heat stress, changes in growing seasons, and altered hydrological cycles. 💡 Data Source: CMIP6 models + Observed station data 📍 Emission Pathway: SSP585 (business-as-usual) Let’s keep pushing for climate resilience, data-driven policies, and climate-smart development. 🌱 #ClimateChange #CMIP6 #DataVisualization #ClimateScience #SSP585 #EnvironmentalEngineering #RidgePlot #Python #Sustainability #GlobalWarming

Between 1985 and 1989, a warming of 0.06 C per decade was observed, while from 2019 to 2023, the sea-surface temperature rose by 0.27 C per decade. This suggests that sea surface temperatures are rising 4.5 times faster since 2019 than they were at the end of the 1980s. The study calculated monthly global mean sea-surface temperature using global satellite data records generated through ESA’s Climate Change Initiative (CCI). The dataset used observations from 20 infrared radiometers on board satellites including ESA’s ERS-1, ERS-2, Envisat, Copernicus Sentinel-3 and two microwave radiometers from 1980 to 2023 to provide a globally accurate temperature trend. The unprecedented warming was the finding of a study published in the journal Environmental Research Letters. The study attributes the rising sea surface temperature to increasing levels of greenhouse gases in the atmosphere. Lead author of the study, Chris Merchant, from Reading University, UK, explained that greenhouse gases trap heat in our atmosphere, resulting in an imbalance in the energy received by our planet from the Sun, and the energy radiated back out to space, resulting in an excess energy imbalance. He said, “This energy imbalance drives climate change. Given the accelerations in ocean warming and evolving climate dynamics, we need ongoing monitoring and data improvements to ensure our climate models can accurately reflect future temperature increases.” The study analyses various factors that influence the warming of the oceans, from weather phenomena such as El Niño, to volcanic eruptions. It found these phenomena cause short-term fluctuations in sea-surface temperatures but do not significantly interrupt the long-term warming trend. Owen Embury, co-author and scientific leader of the ESA-CCI sea-surface temperature project, which contributed the long-term data set, said, “Our study clearly identifies the increasing accumulation of planetary energy as the dominant driver of long-term sea surface warming, while short-term variations from El Niño, volcanic activity and solar changes add variability but do not alter the overall accelerating trend.” The results of the current study will contribute to ESA’s science exploitation project, MOTECUSOMA which is investigating Earth’s energy imbalance and its impact on climate change. Owen added, “Addressing these challenges requires accurate climate projections – increasing ocean heat uptake intensifies extreme weather events, disrupts ecosystems and accelerates sea level rise, making continued observation and model refinement essential.” The SST data record is available from the ESA CCI data portal. Versions formatted to support global climate modelling efforts are available via Obs4MIPs framework. #CCI #ESA #Satellites Global and precise records of sea surface temperature are crucial for tracking and understanding Earth’s energy imbalance. (ESA)