Andy Reisinger

@andyreisinger.bsky.social

8527 Followers 1149 Following

Climate science and policy. Also the occasional photo and random thoughts. Currently serving as Commissioner at He Pou A Rangi, New Zealand Climate Change Commission; former IPCC vice-chair WGIII. Usual disclaimers...

The cover of the album "crisis? what crisis?" by the band Supertramp. A guy sits under sun umbrella in a beach chair, surrounded by an industrial wasteland. The guy and umbrella are in colour, the wasteland is grey.
Screenshot of text: "Significance The natural emissions of methane in pan-Arctic have increased in response to rapid warming and heatwaves. However, the sensitivity of natural methane emissions from the pan-Arctic to climate change remains poorly constrained. We infer the long-term trend of natural CH4 emissions in pan-Arctic from the phase shifts in the atmospheric CH4 seasonal cycle from observations. Our work shows that the sensitivity of Arctic natural biogenic emissions and wildfire emissions to warming is underestimated by the process-based models and the top–down inversion. Our results suggest much stronger positive methane-climate feedbacks in the pan-Arctic and highlight the urgency of reducing anthropogenic CH4 emissions to achieve the goals of the Paris Agreement and the Global Methane Pledge."
first skeet by Leo Hickman, Carbonbrief, says "++BREAKING++ Leading climate scientists in the UK have written to senior editors in broadcast media - and OFCOM and IPSO: "To express our concern about recent media coverage of extreme weather, climate change and net-zero and to urge you…to inform public audiences of the scientific links"" and is followed by a screenshot of the actual letter Second skeet by Aparna Nair says: "I can almost hear the producer telling the interviewer: ‘make sure to end on a positive note, yes, sure, elderly and vulnerable disabled and poor people might literally die, but silver linings!’" and it's quoting a skeet by Ketan Joshi that says "Watching BBC News and they just did 5 minutes with a doctor about how this heatwave is life threatening and the interviewer closed it with "well, it's just an opportunity to have ice cream for breakfast!!". Amazing clip of how the BBC seems just blissfully unaware of what is happening"
A strikingly blue lake nestled in green forest and grassy meadows; a yellow prickly Spaniard (Aciphylla colensoi) in the foreground on a hill overlooking the lake
Black and white photo of a lichen-covered gate in a farmyard fence, illuminated by afternoon sun, with the Hawkdun mountain range visible in the background under a brooding sky
A black and white photograph of the last evening light on Aoraki Mt Cook, with the Hooker River in the foreground; black rocks glistening in the milky silky water
Silhouette of a praying mantis, seen from the other side of a veined leaf
Temperature effect of emission of 1t of methane, and of removing 80t of carbon dioxide for 30 years. The net effect of both actions on temperature is about neutral for the first 10 years, the cooling up to 30 years, and then slight warming beyond 30 years.
PowerPoint slide showing a graph with several scenarios of rising global warming above 1.5 degrees, and two scenarios where global warming exceeds 1.5 degrees for a few decades but then declines back to or below 1.5 degrees by 2100. Next to this are three 'burning embers' bars from the IPCC 6th Assessment Report that illustrate the increasing risk as global warming increases, for unique and threatened species, extreme weather events, and the distribution of impacts.
Advertisement for lecture "Overshoot: challenges and choices after we exceed 1.5°C", by Andy Reisinger, for the lecture series of the Centro Euro-Mediterraneo sui Cambiamenti Climatici (Euro-Mediterranean Centre for Climatic Changes)
A Sankey diagram showing the types and destinations of animal sourced foods produced by high and upper-middle income countries. 70.94% go to high income countries, another 23.32% go to upper-middle income countries, 4.93% go to lower-middle income countries, and 0.81% go to low income countries (all percentages based on trade value). Over 47% reside in low and lower-middle income countries.
Screenshot of the scientific journal page containing the paper: "National temperature neutrality, agricultural methane and climate policy: reinforcing inequality in the global food system" by Colm Duffy*, Carl Doedens, Róisín Moriarty, Hannah Daly, David Styles and Malte Meinshausen, published in Environmental Research Letters, volume 20, Number 9
Screenshot of a figure from the paper, showing that an eventual decline in global temperature could be achieved by three complementary strategies. Any decline in temperature would need additional efforts beyond what is needed to simply halt global warming; none of those options are easy - but there are options that we can take, and that would require planning and preparation now. An overarching point is that limiting how much we exceed 1.5°C in the first place is critical for the feasibility of bringing temperature back down to that level again. That means accelerated efforts to reduce emissions in the near term is critical to keep overshoot (i.e. not just the exceedance, but the eventual decline and return to 1.5°C) a feasible prospect.
Screenshot from the paper showing a figure that sets out that global warming is strongly proportional to cumulative net CO2 emissions - which means that reverting global warming will need globally net negative CO2 emissions. Smaller panels in that figure show that this does not mean that all other aspects of the climate system would revert alongside global temperature; some systems (esp. ecosystems) will exhibit only partial reversibility, and some may be irreversibly changed beyond some thresholds. And sea level will continue to rise even if temperature declines again, only at a lower rate.
Screenshot from the paper, showing a figure that illustrates how the key drivers of risk (climate hazards, exposure, vulnerability, and risks arising from responses to climate change) all affect risk in an overshoot world. The figure seeks to illustrate that even if climate hazards decline again once we get back to 1.5°C, exposure and vulnerability can remain significantly elevated due to the damages during the period when temperature exceeded 1.5°C. A world the returns to 1.5°C will be a significantly more damaged world than one that had never exceeded it; but in most cases, it would be a less damaged world than if temperature remains above 1.5°C forever. Overshoot (i.e. "pursuing efforts to limit warming to 1.5°C" from above that level) is not a good thing, but may be the least bad choice we still have.
Screenshot from the paper, showing an overshoot (exceed-and-decline) trajectory of global temperature, and noting that overshoot can be described both by its magnitude (how much we exceed 1.5°C) and for how long.
A bunch of swirly lines superimposed over a horizontal line that symbolizes global warming of 1.5°C. The conceptual graphic is intended to illustrate the shifting landscape and various tensions around overshooting (that is, exceeding AND returning to) 1.5°C.
The image shows a horizontal bar chart displaying the importance ratings of various cultural and heritage elements. The chart has three color-coded categories: green for "Very/extremely important," yellow for "Moderately important," and orange for "Not important/slightly important." The elements are listed on the left side of the chart, and their importance scores (out of 100) are shown on the right. The items are ranked from highest to lowest importance based on the "Very/extremely important" rating: Churches: 99% very/extremely important Fishing grounds: 96% very/extremely important Connectedness to the community: 95% very/extremely important Cultural identity: 94% very/extremely important Totems (e.g., fish, plant, animal): 89% very/extremely important Traditional medicine (e.g., native plants, herbs): 88% very/extremely important Cultural/traditional practices and customs: 83% very/extremely important Cultural ceremonies (e.g., Yaqona Ceremony): 79% very/extremely important Connectedness to the sea: 79% very/extremely important Connectedness to ancestral land: 62% very/extremely important Burial grounds: 52% very/extremely important Archaeological sites: 50% very/extremely important Historical buildings: 40% very/extremely important
A table of global emission reductions, relative to 2019, in 2030, 2035, 2040 and 2050 to limit warming to 1.5°C with no or limited overshoot. Central estimates for reductions of all GHGs combined are 43% in 2030, 60% in 2035, 69% in 2040, and 84% in 2050. For CO2 emissions specifically the reductions are 48% in 2030, 65% in 2035, 80% in 2040 and 99% in 2050.
Screenshot of the He Pou A Rangi Climate Change Commission's vacancies web page. "Work with us. Be part of a game-changing organisation."
Photograph of a mountain hut completely encrusted in ice on one side, with a clear dark blue sky beyond
A climber is approaching a hut that is completely covered in horizontal icicles after a severe storm, but the sky is clear and one can see the shadow of the mountain stretching into a red-purple-blue horizon
Screenshot of journal article page: Is limiting the temperature increase to 1.5°C still possible? https://doi.org/10.1177/29768659241293218
A densely moss covered forest scene. A large fallen log is blocking the path, and various gnarly trees with moss covered stems and branches stand behind it. Almost everything is green.
Two images of Rangitoto island side by side, sunrise on the left, moonrise on the right
View from below the summit of Mt Taranaki, looking down a steep scree slope on a sea of clouds in evening light. A large boulder in the foreground both blocks the way and offers shelter in the dying light.
A small stream running alongside the margin of a forest; trees are partly covered in moss, some ferns and grasses in the foreground.
A photo of Te Ara Kairaumati (Lake Matheson) on the west coast of New Aotearoa New Zealand's south island, on a perfectly still morning, mirroring snow-covered Aoraki (Mt Cook) and Te Horokōau (Mt Tasman) in the background.
Screenshot of submission portal for NextGen Voices: quarter-century haiku
A black and white photograph of Aorangi (Mt Cook), the highest mountain of New Zealand, with the Hooker river in the foreground.
A graph showing relative sea level rise at 4 ports of New Zealand, and the average across the 4 ports, and a quadratic fit to the average, demonstrating that sea level rise has been accelerating over time.
A line graph showing the accelerating rise in atmospheric methane abundance from before 1990 to 2023 (with strong growth after 2006, and even stronger growth during 2020-2022), and the declining isotope ratio of 13C:12C after 2006 with an even more rapid decline during 2020-2022.
A bar chart showing the level of subsidies for renewable energy and fossil fuels for a range of countries. In almost all countries, the level of support for fossil fuels far outweighs the support for renewable energy.
Screenshot of news headline "Luxon [New Zealand's Prime Minister] takes crack at ANZ boss Antonia Watson over capital gains tax support"
The cover of the report "Strategic Dialogue on the Future of EU Agriculture"
Two graphs. One graph shows projected changes in GDP/capita in 10 world regions as well as the global average. GDP/capita rises in all world regions by about the same amount, but GDP/capita in Africa and several other regions remains well below that in North America, Pacific OECD, and Europe. A second graph shows the ratio of GDP/capita between North America and the world, North America and Africa, and Africa and the world. The ratio of North America/Africa declines from currently more than 12 to about 3.3 in 2100; some people refer to this as 'convergence', others describe it as 'continued severe inequality'.
Domain Year Description Livestock 2030 Methane emissions from the livestock sector have been reduced by 25 percent compared to 2020. 2050 Total factor productivity for livestock has grown at 1.7 percent per year globally. Fisheries & Aquaculture 2030 100 percent of fisheries under effective management and all illegal, unreported and unregulated activities phased out. 2040 At least 75 percent growth in global sustainable aquaculture. Production compared to 2020 level. Crops 2050 Total factor productivity for crops has grown by 1.5 percent per year globally. 2050 Total factor productivity for crops has grown by 2.3 percent per year for low-income countries. Enabling healthy diets for all 2030 All the countries have updated their food-based dietary guidelines to provide context appropriate quantitative recommendations on dietary patterns. 2030 All countries have legislation restricting food advertisement targeting children. Forest & wetlands 2025 Zero Net-Deforestation is
Food Security and Nutrition Goals and contributing to the 1.5 C agenda 2025 150 million people out of hunger compared to 2020. Emissions from drained carbon soils are cut by 5% compared to 2020. 2030 Chronic hunger eliminated. Gross GHG emissions of agrifood systems cut by 25 percent. 2035 Number of people that could not access to healthy diets cut by half compared to 2020. Agrifood systems are CO2 neutral, only other GHG are net emitters. 2040 Number of people that do not consume a healthy diet has been cut by half compared to 2020. N2O emissions of the agrifood systems are halved compared to 2020. 2045 Number of people that could not access to healthy diets has been reduced by 85 percent compared to 2020. CH4 emissions of the agrifood systems are halved compared to 2020. 2050 Everyone consumes healthy diets. Agrifood systems are a net carbon-sink (-1.5 Gt CO2eq per year).
Screenshot of article header: authors Andy Reisinger and Oliver Geden. Summary of article: The world looks almost certain to reach and then exceed global warming of 1.5°C during the 2030s, given recent trends and limited near-term action. The next-best option still within reach is to ensure this exceedance is both limited and temporary, by bringing global warming levels back down below 1.5°C as soon as possible and by 2100 at the latest. In this primer, we set out the key elements that would make such a ‘‘temporary overshoot’’ trajectory a relevant and feasible prospect. We elaborate on the origins of temporary overshoot as a concept in the scientific literature as well as its emerging role in international climate policy, the need for a typology of risks that a future decline in temperature would reduce or avoid, and the emission pathways that could achieve a return of global warming levels to below 1.5°C, along with their feasibility and implications for climate policy.
A chart showing the largest producer countries of coal, oil and gas. China is first by a significant margin, thanks to coal, Isis second, Russia third (both a mix of all three), Saudi Arabia fourth (mainly oil), Australia fifth (mainly coal). Etc.
A schematic diagram outlining 4 principles of agriculture breakthrough: sustainable increases particularly in low and middle income countries; reduced emissions from the agrifood sector; improved soil, water resources and natural ecosystems; improved adaptation and resilience. The diagram suggests 5 pathways to achieve this: reduce unsustainable consumption; increase production of sustainable and healthy foods particularly in low/middle income countries without expanding agricultural land use; reduce damage to natural resources; reduce emissions; and prioritise the needs and interests of smallholder producers.
A series of graphs showing CO2 and CH4 emissions declining into the future (left), the warming caused by those emissions compared to the warming caused by emissions up to the year 2020 (middle), and the warming caused by future emissions relative to those emissions not occurring (right).
Two photographs side-by-side of Rangitoto Island, Tāmaki-Makaurau, one with the sun rising behind it and an orange sky, the other with the moon rising behind it and a blue sky
Text: Your submission stated that the work you commissioned “demonstrates a significant development in the scientific understanding of what is required for New Zealand to achieve no further warming from biogenic methane since the commencement of Section 5T of the Climate Change Response Act in 2019”. After reading the study you commissioned, I can find no support for this conclusion. Barth et al.’s work represents no significant development at all in the science since I published my own findings on this topic in 2018. This is a pity - by repeating work that has already been done, an opportunity to move the debate forward has been missed. This is not “new science” and it leaves us exactly as I had previously stated the position to be – namely, that the sustained contribution to atmospheric warming that New Zealand makes through the emission of agricultural methane is a matter of choice, and choosing to maintain this warming at the current level is to claim a “right” to a cer
Coastal sunset with orange sky and purple/blue ocean and black rocks in the foreground. On the horizon one can see mountains of the South Island (seaward Kaikouras), on the right middle distance is a silhouette of Tapu te ranga motu.
A set of four global maps showing asset and production values, in total and per capita, of livestock. There are data limitations on asset values. African countries tend to score low on both total and per capita production value. Some countries have high per capita production value but low total production value, and vice versa.
A farm gate in later afternoon sun, with a brooding sky above and a low mountain range on the horizon
Screenshot of article in Science magazine: Rebalance attention from global target setting toward national climate politics and policy, by Navroz Dubash
A picture of part of the milky way, including the Southern Cross, with three people silhouetted in the foreground
A gravel road with a fork going off to the right, under a big blue sky with some white clouds. A road sign stands on the side. The ground is covered in dry yellow grass.
A photo of the sun setting on the snowy peak of Mt Cook, with the Hooker river in the shadow foreground