56 million-year-old Eocene global warming may indicate a wetter future
Modeling of Earth's response to global warming has suggested dry regions will become more arid and wet regions will experience more precipitation, with an uneven distribution of moisture in the atmosphere. With
enhanced seasonality, there will likely be more severe consequences for our remote and urban communities, as well as natural ecosystems.
While there has been some uncertainty over low latitude (tropics, <15° N/S) and mid-latitude (15—30° N/S) hydrological responses to global warming, high latitudes (>60° N/S) are predicted to become wetter and subtropical regions (15°–30° N/S) drier. However, scientists have studied ancient global warming events to suggest that, at least for the subtropics, this may not be the case.
The Early Eocene Climatic Optimum (56–48 million years ago) was one of the warmest intervals of the last 66 million years, with mean global surface temperatures over 14°C warmer than present. Atmospheric carbon dioxide levels were elevated to >1,000 parts per million (ppm; by comparison modern levels are ~400 ppm) and mean sea surface temperature was up to 16°C warmer than pre-Industrial temperatures, while latitudinal temperature gradients (the temperature difference between the equator and poles) peaked at 22°C. Intergovernmental Panel on Climate Change (IPCC) reports predict that Eocene climate could be reached by 2100, under worse-case scenario models.
Researchers at the University of Southampton's School of Ocean and Earth Science and global collaborators have used the Deep-Time Model Intercomparison Project (DeepMIP) to reconstruct global mean rainfall patterns during the early Eocene across the planet. Their research is reported in Paleoceanography and Paleoclimatology.
Meanwhile, physical evidence of the Eocene climate conditions was obtained from palaeontological proxies, these being preserved fossil leaves, pollen and spores. Leaf size and shape in particular can be an extremely useful indicator of moisture levels in the surrounding environment, and oftentimes the preserved leaves can be identified to their nearest modern relatives with assumptions being made that they have similar functions and ecological preferences, Therefore, if Eocene leaves can be matched to leaves that thrive in wetter conditions in the modern day, scientists can assume this was the case millions of years ago too.
The DeepMIP simulations work from the pre-Industrial level up to nine times that CO2 concentration for worse-case scenario models. As greater CO2 concentrations result in enhanced warming, the researchers found that higher global mean surface temperatures correlated with increased mean annual precipitation estimates. This is most noticeable in high latitudes, with models predicting a 9.1% increase in mean annual precipitation with each 1°C increase in temperature, while global average mean annual precipitation increased 2.4% per 1°C warming. Tropical and subtropical mean annual precipitation was still relatively high as well, calculated as >2–4 mm/day.
Overall, the models simulate that when latitudinal temperature gradients are weaker, moisture in the atmosphere in the tropics is less likely to be dispersed across the planet, contributing to more precipitation in these areas. Tropical and high-latitude regions are characterized by positive precipitation and evaporation regimes, leading to wetter conditions, while the subtropics are anticipated to experience opposing negative precipitation and evaporation values, with more aridity. Earth's connected systems make the latter more complex though as humidity and atmospheric circulation interfere with subtropical moisture budgets, resulting in greater precipitation and less evaporation than modeled.
Comparing the simulations to fossil proxy data from vegetation suggests that these models could be underestimating the precipitation levels from past climate change and thus scientists must use a multi-pronged approach to modeling current and future implications of global warming. Importantly though, comparison to global warming events in the deep past offers insights for where we may be headed in the future so humanity can plan mitigation strategies to deal with progressively drier or wetter conditions, depending on where they are in the world.
More information: Margot J. Cramwinckel et al, Global and Zonal‐Mean Hydrological Response to Early Eocene Warmth, Paleoceanography and Paleoclimatology (2023). DOI: 10.1029/2022PA004542.
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China and India do more than you think to fight global warming
With world leaders having just met in Paris to discuss the environmental catastrophe facing the planet, coming on the heels of the northeastern US being choked on soot from Canada's worst-ever forest fires, Americans are gradually realising that climate change is today's problem — not tomorrow's. Yet many continue to think that the worst offenders are developing economies, especially China and India. This mindset, while never accurate, ignores how those very countries are taking the leadership mantle in the transition to green energy.
Part of the problem is US domestic politics. A deep and lingering partisan divide over climate was borne in a cynical $13 million advertising campaign launched by fossil-fuel interests in 1997 to prevent US ratification of the proposed Kyoto climate treaty. They made the case that the US was doing more than its fair share of sustaining global burdens, including foreign aid and peacekeeping, and that the same was happening in efforts to mitigate climate change.
The campaign succeeded. In July 1997, the US Senate overwhelmingly (95-0) approved the so-called Byrd-Hagel resolution opposing ratification of any binding climate treaty that did not impose equivalent obligations on developing nations. President Bill Clinton's administration never put the Kyoto agreement up for a vote. Public opinion on climate has never shaken that mentality: Majorities of Americans favour renewable and clean energy in place of coal and oil, but retain a deep suspicion that the US is again doing the heavy lifting.
While the world has lost precious time because of US hesitation, there has been progress around the globe on combatting climate change. Clean energy technologies — including wind and solar power, battery storage and electric vehicles — are now competitive and in many cases cheaper than coal, oil or gas. That progress has been led not only by Europe, but by China, India and other emerging markets such as Chile, Morocco and Vietnam. The world's cheapest electricity today is generated by the sun in the oil-rich United Arab Emirates.
That progress in the global south is important, because today emerging markets, while still smaller per-capita emitters compared to the US, are responsible for a much larger and steadily growing share of total current greenhouse gas emissions: China's are about 50% larger than America's; together, India and China account for twice as much warming as the US. But that doesn't mean they aren't giving Uncle Sam a run for his money as climate leaders.
The Earth's atmosphere doesn't care what flag is flying over the spot on the planet emitting a given molecule of CO2 or methane. Rather, we must weigh whether a given emissions source is using the least climate-damaging energy to meet the needs of its stakeholders. The atmosphere generously provided us with the ability to emit limited volumes of greenhouse gases, but we are now running out, and each have only a small share remaining.
And here, so far, China and India continue to use them much less wastefully than the US, European Union, Russia or Saudi Arabia.
Per capita, the average inhabitant of China is responsible for only half as much in greenhouse emissions as a US resident. The average Indian uses only one-seventh as much CO2, methane and other harmful gases. And on the most important predictor of our climate future — the speed with which clean energy is being deployed to replace fossil fuels — China and India are emerging as leaders.
China now generates 650 terawatt-hours of wind electricity, almost twice as much as America. It provides a third of the world's solar power, 330 terawatt-hours, more than twice as much as the US. Chinese authorities are building far more renewable energy than anyone else. They expect renewables to power a third of their grid by 2025.
Globally, China is also the major provider of solar capacity to other countries, producing 75% of the world's photovoltaic capacity. It produces 57% of the world's electric vehicles. China has not only developed the largest domestic EV market, it has become the major EV exporter, outpacing the historically dominant automakers in Japan, Germany and the US.
It is true that China is building coal-fired power plants at a record pace — more the rest of the world combined. This in in part because local governments like the construction dollars they bring in. However, analysts suspect that many will never find major use, and they are being swamped by renewable power. And in spite of all those coal plants, China already gets more of its power from renewables than the US — 50% vs. 40%.
China is flooding its power market with clean energy. In 2022 it invested $546 billion in accelerating its transition to renewables, three times the EU's $180 billion and, relative to the size of its economy, four times the US investment commitment. In the first four months of 2023, China increased its installed solar capacity by an astonishing 36%, and last month announced it is on track to install as much new solar in one year as the entire US solar infrastructure.
Let's understand the magnitude of this Chinese rate of progress. It expects to inaugurate 200 gigawatts of renewable power versus 50 gigawatts of coal this year.
India, of course, started with a far smaller and less electrified economy; its current numbers are not as impressive as China's. It is, however, moving much faster than any nation ever has at an equivalent development level. India already derives 40% of its electricity from zero-carbon sources, matching the US and catching up with China. It has announced a five-year moratorium on approving new coal plants. India's energy-generation additions in 2022 were 92% wind and solar. The US still relies on natural gas for about 20% of its new generation; at this rate, in a few years the US grid will be more fossil-fuel intensive than India's.
According to the International Energy Agency: "Renewable electricity is growing at a faster rate in India than any other major economy, with new capacity additions on track to double by 2026."
And India's innovative "round the clock" approach to wind and solar auctions has led the developing world for bringing down the cost of renewable power. New clean electricity in India is two or three times as cheap as in most of its South and Southeast Asian neighbours, or the US.
So, can Americans relax now that we know India and China are deeply invested in the energy revolution? Hardly. By any reasonable standard, the US needs to worry about falling behind China and India in this new world of energy.
The Joe Biden administration's Inflation Reduction Act, with $370 billion set aside for renewables, can fairly be said to put the US back in the clean-energy game. But, dating back to the splintered politics set up by the Byrd-Hagel tragedy two and a half decades ago, we still have a long way to go.
Disclaimer: This article first appeared on Bloomberg, and is published by special syndication arrangement
Global development banks unveil Paris alignment rules, leaving experts underwhelmed
Ten multilateral development banks have agreed on how to make sure their investments meet climate goals. But experts told Climate Home the rules do not go far enough.
A group of leading global development banks has agreed on long-awaited principles to align new financing with national and international climate goals.
Ten multilateral development banks (MDBs) – including the World Bank – have defined a multi-step process to establish whether projects meet the goals of the Paris Agreement, which aims to limit global warming to well below 2°C and to “pursue efforts” to keep it under 1.5°C.
The principles, which make good on a commitment first made by MDBs in 2017, require projects to line up with national climate plans and include a list of acceptable activities.
But analysts and campaigners are sceptical whether the rules will divert public money away from polluting activities and prevent global warming. A key criticism is that the framework does not explicitly prohibit financing for fossil fuel activities.
Focus on national plansFor a proposed investment to be considered under the new principles, it needs to align with countries’ climate strategies submitted to the UN, known as nationally determined contributions (NDCs).
If an activity – even a highly polluting one – appears in the relevant NDC, it will be waved through to the next step. The exceptions to this are support for coal mining, coal power plants and peat extraction, which are not considered Paris-aligned in any circumstance .
Laura Sabogal, policy advisor at E3G, considers it “very likely” that the banks’ portfolios will actually overshoot the Paris Agreement threshold because of the heavy reliance in the decision-making process on national climate plans that are “not robust enough”.
What does “unabated” fossil fuels mean?
“These documents are extremely vague, not uniform or comparable,” Sabogal told Climate Home News. “Many NDCs are not aligned with a 1.5C, or even 2C, trajectory. If you aggregate all of these investments it is very likely the banks are not actually aligning with the goals of the Paris Agreement.”
According to Climate Action Tracker, no country’s NDC is compatible with 1.5C of global warming.
The UN Environment Programme says the current pledges made collectively by countries in their NDCs put the world on track for a temperature rise of between 2.4C and 2.6C by the end of the century.
First step in reformsMDBs hold over $1.8 trillion in assets, giving them an outsized influence over the direction of funding flows toward developing countries in particular. They have long been accused of continuing to fund polluting projects and not doing enough to support climate-friendly ones. A growing coalition of nations, gathered in Paris last week, has been calling for deep reforms.
Fossil fuels, planes, ships and shares – What will be taxed for climate funds?
The new principles were agreed on by the African Development Bank, Asian Development Bank, Asian Infrastructure Investment Bank, Council of Europe Development Bank, European Bank for Reconstruction and Development, European Investment Bank, Inter-American Development Bank Group, Islamic Development Bank, New Development Bank and the World Bank Group.
Each lender will now have to adopt them into their own methodologies and use them in vetting investment proposals.
Across the ten lenders, the work to turn high-level principles into something tangible is at very different stages. At one end, the European Investment Bank says all its new investments have been Paris aligned since the start of 2021. Meanwhile, the African Development Bank hopes to reach that target by 2025.
If fully implemented, the new framework could mark a degree of progress toward more climate-friendly operations for some lenders.
Although mining and electricity generation from coal and peat are in an exclusion list of projects considered incompatible with the emission reduction goals of the Paris Agreement, this does not amount to an outright ban on investing in these activities. But experts believe it should further discourage development banks to fund them.
Multilateral banks’ investments in industrial livestock undermine their Paris climate commitments
Of the MDBs that signed up to this initiative, the Islamic Development Bank and the African Development Bank are the only ones without an explicit commitment to end coal finance. The African lender’s president Akinwumi Adesina pledged to scrap coal funding in 2019, but this has yet to be formally reflected in the bank’s energy policy.
Aki Kachi, an analyst at the New Climate Institute, told Climate Home News that “inevitably, it was always going to be the lowest common denominator between all the banks”.
“Some may go further and interpret it in a more ambitious way, others will use all of the flexibility to carry on almost with business as usual,” he added.
Campaigners pushing for MDBs to stop funding all fossil fuel operations were also left disappointed by the exclusion of any mention of oil and gas in the framework. “As they are not part of the exclusion list these will continue to be assessed on a case-by-case basis,” said Sabogal.
Political considerationsThe document agreed on by the development banks draws a scenario in which a country is seeking funding for a fossil-fuel-powered technology. If, for instance, the country’s climate strategy states specifically that technology needs to be phased out by 2035, a project with a ten-year lifetime submitted in 2025 would not be considered aligned. But, if the NDC does not mention that fossil fuel activity at all, it will be allowed to progress to the next stage of assessment.
The other steps in the process look at the consistency with sector-specific decarbonisation pathways, the feasibility of cleaner alternatives and the risk of creating stranded assets.
Kachi said ultimately a lot would depend on the interpretation given by the banks’ officers, which is often driven by the political dynamics of their governance.
“We can’t assume this is merely a technical exercise,” he said. “It is very much a political one. The strategies are driven by political agendas within the banks’ management and shareholders. It’s only going to have an impact if the shareholders want that result.”
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