Climate & environment

Topics represented

Climate & environment (50) · Cooperación internacional (16) · Derecho ambiental (12) · Gobernanza ambiental (11) · Cambio climático (8) · Paleoclima (8) · British Empire (7) · Oceans, navigation & cartography (7) · Política climática (7) · Biodiversidad (5) · Famine, health & environment (5) · Hydrography & bathymetry (5)

Records and sources

Ordered by start date. Long lives and processes may begin before the period you want to study.

1. c. 720000000 BCE–c. 635000000 BCE

   Cryogenian glaciations

   Geological records place the Sturtian and Marinoan glaciations within the Cryogenian Period, roughly 720 to 635 million years ago. The ice extent and the degree to which the planet may have been ice-covered remain under study; this entry marks a stratigraphic interval, not a uniform climatic state.

2. c. 55900000 BCE–c. 55700000 BCE

   Paleocene–Eocene Thermal Maximum

   The Paleocene–Eocene Thermal Maximum (PETM), dated approximately 55.9 to 55.7 million years ago, is identified in multiple paleoenvironmental archives as a geologically rapid warming episode. Temperature and carbon reconstructions retain uncertainties of resolution and mechanism; it is not a direct analogue for a human historical period.

3. c. 2580000 BCE–c. 11700 BCE

   Quaternary glacial–interglacial cycles

   Since the beginning of the Quaternary, about 2.58 million years ago, archives such as ice cores, marine sediments, and glacial landforms record cycles of ice ages and interglacial climates. Their expression was not identical in every region and reflects interactions among orbital forcings, greenhouse gases, oceans, ice, and feedbacks.

4. c. 129000 BCE–c. 116000 BCE

   Last Interglacial

   The Last Interglacial, approximately 129,000 to 116,000 years ago, is reconstructed from marine, ice, and terrestrial archives. It helps study sea level, ice, and temperature responses under conditions different from today’s, but comparisons depend on region and proxy used.

5. c. 23000 BCE–c. 19000 BCE

   Last Glacial Maximum

   The Last Glacial Maximum is placed approximately 23,000 to 19,000 years ago. Ice, ocean, and vegetation indicators show a colder Earth with extensive ice sheets; local values and consequences differ among reconstructions, so no identical environmental experience is inferred for all populations.

6. c. 18000 BCE–c. 11700 BCE

   Last deglaciation transition

   Between roughly 18,000 and 11,700 years ago, the climate system moved from the last glacial period toward the Holocene. Records show long-term global warming interrupted by abrupt regional changes; the chronology and magnitude of those changes depend on archive and location.

7. c. 12900 BCE–c. 9700 BCE

   Younger Dryas

   The Younger Dryas was an abrupt return to colder conditions, especially visible in many North Atlantic records, before the beginning of the Holocene. Synchrony, magnitude, and mechanisms were not expressed the same way across the planet; this entry does not by itself attribute social or cultural changes to the episode.

8. c. 9700 BCE

   Formal beginning of the Holocene

   The International Commission on Stratigraphy defines the base of the Holocene at 11,700 years before 2000, using a reference point in Greenland’s NGRIP2 ice core. It is a stratigraphic definition based on an ice proxy; it does not imply that climatic change occurred in the same way or on the same date in every region.

9. c. 6250 BCE

   8.2 ka climate event

   The Northgrippian subdivision of the Holocene is fixed at a climate event dated 8,236 years before 2000, prominently recorded in the NGRIP2 core. Other proxies show differing regional expressions; the marker does not turn archaeological correlations into a single cause of social change.

10. c. 2250 BCE

    4.2 ka climate event

    The base of the Meghalayan is defined at 4,250 ± 30 years before 1950 through an isotopic signal in a speleothem from Mawmluh Cave (India), associated with weakened monsoon conditions in parts of South and Southeast Asia. The evidence does not justify explaining the trajectories, crises, or continuities of all societies in that period through a single climate episode.

11. c. 536–c. 550

    Volcanic forcing and climate anomalies of 536–550

    Ice, tree-ring, and geological evidence link a sequence of volcanic stratospheric aerosols with climate anomalies between 536 and 550; a large Ilopango eruption is dated around 539/540. Attribution of particular effects on famine, conflict, or political change remains debated and is not presented here as exclusive causation.

12. c. 950–c. 1250

    Medieval Climate Anomaly

    The term “Medieval Climate Anomaly” is often used for relatively warm conditions in some regions between about 950 and 1250. IPCC syntheses caution that its timing and signal were not spatially uniform; this entry therefore uses a comparative reconstruction label, not a homogeneous global warm period or a sufficient explanation for historical processes.

13. c. 1257

    Samalas eruption

    The 1257 Samalas eruption in present-day Indonesia left a sulfate signal in ice cores and is studied as a major thirteenth-century volcanic forcing. Reconstructions of its magnitude and regional climatic responses are refined as new evidence emerges; temporal coincidence alone does not demonstrate specific social effects.

14. c. 1450–c. 1750

    Early interval of the Little Ice Age

    Paleoclimate reconstructions describe a relatively cool multi-century phase, often termed the Little Ice Age, approximately from 1450 to 1850. This entry stops at 1750 because of the catalogue’s scope: neither onset, intensity, nor impacts were uniform across regions, and they are not automatically attributed to one forcing.

15. c. 1627–c. 1650

    Colonization of Barbados and the shift to slave-based sugar plantations

    English settlers occupied Barbados in 1627; over subsequent decades, sugar, consolidated estates, and the mass importation of enslaved Africans displaced much small production and European indentured labor. The “Barbados model” joined capital, monoculture, racial law, and social and environmental devastation

16. 1769–1773

    Famine, smallpox, and Company revenue rule in Bengal

    Drought, harvest failure, and epidemic produced catastrophe under the Company’s new revenue regime, which maintained heavy demands and provided inadequate relief. Mortality estimates—including the traditional figure of ten million—are disputed and must not be rendered as an exact count

17. 1845–1852

    The Great Famine transforms Ireland and the Atlantic

    Potato blight repeatedly destroyed the crop, but unequal landholding, dependence, and state policy magnified the catastrophe. Roughly one million died and another million emigrated—estimates rather than exact counts—accelerating depopulation, diaspora, and nationalism under Union government

18. 1872–1876

    Challenger conducts a global ocean survey

    The HMS Challenger expedition circumnavigated the globe measuring depth, temperature, salinity, currents, and sediments while collecting organisms. Its stations were scattered points rather than a complete map, but they established a quantitative, multidisciplinary foundation for modern oceanography and bathymetry.

19. 1876–1878

    Drought and imperial policy magnify the Great Famine

    Monsoon failure and El Niño struck southern and western India while prices, exports, taxation, and restrictive state relief magnified mortality. Estimates vary widely—millions died, but no single total is secure—and the disaster prompted famine codes and nationalist criticism

20. 1903–2026

    GEBCO coordinates a global bathymetric chart

    A commission chaired by Albert I of Monaco initiated the General Bathymetric Chart of the Oceans in 1903 to harmonize nomenclature and assemble soundings. GEBCO evolved from printed sheets to global digital atlases and grids; in 2026 it continues as a joint IHO–UNESCO-IOC program.

21. 1909

    Sweden’s first national parks

    In 1909, Sweden passed a national-parks law and created nine parks; the Swedish Environmental Protection Agency identifies them as Europe’s first. The milestone shows the early consolidation of a state protected-area instrument outside the United States, without treating that legal form alone as sufficient for all biodiversity or for every local relationship with land.

22. 1920–2006

    Marie Tharp

    An American geologist and cartographer, Tharp transformed echo-sounding profiles and seismic data into coherent maps of submarine relief with Bruce Heezen. By identifying the Mid-Atlantic Ridge rift valley, she made evidence for seafloor spreading visible despite barriers that initially kept her from going to sea.

23. 1925

    Creation of Albert National Park (now Virunga)

    In 1925, Albert National Park—now Virunga—was created in the then Belgian Congo to protect mountain gorillas and other Albertine Rift environments; UNESCO describes it as Africa’s first park. It was a conservation measure instituted under colonial administration. That context means early African parks should not be presented as politically neutral precedents: relations of access, authority, and land require situated historical analysis.

24. 1926

    Proclamation of Kruger National Park

    South Africa’s 1926 National Parks Act formally proclaimed Kruger National Park by bringing together the Sabie and Shingwedzi reserves. It was an important expansion of the state-reserve model in southern Africa; its aims of protection, research, and public visitation do not by themselves establish uniform ecological outcomes or erase the territory’s social history.

25. c. 1930–c. 1940

    Dust Bowl in the Great Plains

    During the 1930s, severe drought and dust storms affected the Great Plains of the United States and Canada. Public sources point to an interaction among drought, erosion, and poorly adapted land-use practices, not a single cause; the episode damaged soils, crops, and livelihoods, but its intensity and experience varied within the region.

26. 1933–1936

    London Convention on African fauna and flora

    The 1933 London Convention, in force from 1936, proposed national parks, strict reserves, hunting controls, and trophy-trade regulation to protect fauna and flora, particularly in Africa. Its text expressly contemplated colonies, overseas territories, and mandates. It is therefore also evidence of the colonial framework of part of early international conservation; the treaty organized reserves and species rather than a procedure for community consent or land tenure.

27. 1935

    United States Soil Conservation Act

    In April 1935, amid the Dust Bowl, the United States passed the Soil Conservation Act and created the Soil Conservation Service within the Department of Agriculture. The measure recognized soil and moisture erosion as a public problem and organized technical assistance; it was a specific national response, not a universal solution to degradation or to its social and economic causes.

28. 1940–1942

    Convention on Nature Protection in the Western Hemisphere

    The inter-American convention opened for signature in 1940 and entered into force in 1942. It defined national parks, reserves, and nature monuments, and called for measures for migratory birds crossing American borders. It was an early norm of cooperation, but left the adoption and implementation of measures to governments; it did not guarantee equivalent protection among countries.

29. 1943–1944

    The Bengal famine exposes wartime priorities

    Millions died in Bengal in a crisis shaped by lost imports, inflation, military procurement, distribution failure, “denial” policies, delayed relief, and crop damage. Estimates commonly range from two to three million, but the total and the weight of each cause remain debated

30. 1952–1963

    British nuclear tests at Monte Bello, Emu Field and Maralinga

    With the agreement and support of the Australian government, the United Kingdom conducted nuclear trials at the Monte Bello Islands, Emu Field and Maralinga between 1952 and 1963. Tests and experiments contaminated lands inhabited by Aboriginal peoples, especially Anangu and Maralinga Tjarutja communities, and also exposed service personnel. The 1985 McClelland Royal Commission criticized protection of Indigenous people and safety management, revealing how a postcolonial military relationship preserved hierarchies and shifted risks onto local communities