9.3: Accessible Descriptions
- Page ID
- 51188
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Figure 8.1.1: Sediment Core Section
Photograph of a sediment core collection displayed in a rectangular wooden storage tray. The tray contains eight horizontal core sections arranged in parallel rows. Each row holds cylindrical core samples that have been split lengthwise and laid flat for examination. Small labels at the ends of the rows indicate depth intervals, ranging approximately from 926.42 meters to 930.62 meters, suggesting the cores were recovered from a subsurface drilling project.
The core sections display variations in color, texture, composition, and structure. Most intervals consist of light-colored, fine-grained sedimentary material with visible layering and subtle banding. Several sections contain fractures, cracks, and breaks where the core has been fragmented during drilling or handling.
One interval in the upper half of the tray contains a markedly different zone of coarse, multicolored material composed of angular fragments embedded within a finer matrix. This interval contrasts sharply with the surrounding fine-grained layers and may represent a different depositional environment or a disturbed section.
Multiple gray markers and circular reference disks are placed on top of the cores at selected locations. These markers appear to identify features of interest, sample locations, fractures, or stratigraphic boundaries for analysis. The core segments vary in continuity, with some rows nearly intact and others broken into multiple pieces.
The image illustrates how sediment cores preserve a vertical record of subsurface geology, allowing researchers to study changes in sediment composition, depositional processes, environmental conditions, and geologic history through depth.
Figure 8.1.3: Ice Core
Photograph showing a long cylindrical ice core positioned horizontally on a metal measuring cradle inside a laboratory or cold-room research facility. The ice core appears nearly transparent to translucent white and has been extracted as a continuous cylinder from an ice sheet or glacier for scientific analysis.
The core rests in a metal channel mounted above a workbench. A ruler or measuring scale runs alongside the core, allowing researchers to determine its length and position during processing. Based on the visible scale and the portion shown in the image, the ice core section appears to be approximately 1 meter (about 3 feet) long, which is a common length for ice-core segments recovered during drilling operations.
The exposed circular end of the core reveals a smooth cross-section. Subtle bands, bubbles, and variations in transparency are visible within the ice, representing differences in snow accumulation, air content, dust concentration, and other environmental conditions preserved when the ice formed. The dark band
described in the figure caption is approximately 80 cm from the closest end of the core.
The surrounding laboratory contains equipment commonly associated with ice-core handling and storage, including metal shelving, cylindrical storage tubes, insulated containers, and processing surfaces. The environment appears organized for the measurement, logging, cutting, and sampling of ice cores.
Ice cores such as this are commonly collected from polar ice sheets in Antarctica and Greenland and can preserve records of past climate conditions. Scientists analyze trapped air bubbles, isotopes, dust particles, volcanic ash, and chemical compounds within the ice to reconstruct past temperatures, atmospheric composition, precipitation patterns, and greenhouse gas concentrations.
Figure 8.1.4: Past 65 Million Years of Climate Change
A multi-axis climate history figure titled "65 Million Years of Climate Change" traces climate evolution from approximately 65 million years ago to the present. Time runs from older on the left to the present on the right. Geological intervals labeled along the figure are the Paleocene (Pal), Eocene (Eo), Oligocene (Ol), Miocene (Mio), Pliocene (Pli), and Pleistocene (Plt).
The main jagged line represents benthic oxygen isotope composition, delta-18-O, using the right vertical axis from approximately 0 to 5 per mil. The scale is inverted, with 0 at the top and 5 at the bottom. In this record, increasing benthic delta-18-O generally corresponds to decreasing deep-ocean temperature and/or increasing global ice volume.
The large inset covering the Paleocene and Eocene converts the early isotope record to polar-ocean-equivalent temperature change, with values from approximately 4°C to 12°C. Temperatures begin near 7–8°C around 65 million years ago, increase through the Paleocene, and undergo the Paleocene-Eocene Thermal Maximum (PETM) near 56 million years ago. The record reaches its highest sustained values during the Eocene Optimum, at roughly 11–12°C around 52–50 million years ago. A pronounced long-term cooling follows: equivalent temperatures decline to approximately 8°C by 45 million years ago, 6–7°C around 40 million years ago, and approximately 4°C by 35 million years ago.
Near 34 million years ago, the figure labels Antarctic Glaciation, associated with an abrupt change toward larger delta-18-O values and the development of a major Antarctic ice sheet. The Oligocene remains substantially cooler than the early Eocene.
Around 23 million years ago, an event labeled Antarctic Thawing corresponds to a pronounced shift toward warmer conditions and/or reduced Antarctic ice. This is followed by renewed cooling and Antarctic Reglaciation around 14 million years ago.
A second inset over the most recent portion of the record expresses climate change as an equivalent Vostok Antarctic temperature anomaly, with a vertical scale from approximately +2°C to -8°C. The values trend downward toward the present, indicating substantial late-Cenozoic cooling.
The final few million years are labeled Rapid Glacial Cycles. Benthic delta-18-O reaches approximately 4–5 per mil, reflecting colder temperatures and larger global ice volumes associated with repeated Pleistocene glacial-interglacial cycles.
Overall, the figure depicts Earth's transition from the exceptionally warm early Cenozoic to a progressively colder climate with permanent Antarctic glaciation and, eventually, recurring large Northern Hemisphere ice sheets.
| Approx. age (million years ago) | Equivalent temperature change | Feature / interpretation |
|---|---|---|
| 65 | ~7–8°C | Warm early Paleocene conditions |
| 62 | ~8–9°C | Temperature rises with short-term fluctuations |
| 60 | ~8–9°C | Warm Paleocene climate |
| 58 | ~8°C | Brief cooling before major early Eocene warming |
| ~56 | ~10–12°C | PETM; abrupt warming excursion |
| 54 | ~10–11°C | Continued warming after PETM |
| 52 | ~11–12°C | Approaching peak Eocene warmth |
| 50 | ~11–12°C | Eocene Optimum; highest sustained temperatures in inset |
| 48 | ~10–11°C | Beginning of long-term cooling |
| 46 | ~9–10°C | Continued cooling |
| 44 | ~8°C | Noticeable decline from Eocene maximum |
| 42 | ~7–8°C | Cooling continues, with short-term fluctuations |
| 40 | ~6–7°C | Substantially cooler than Eocene Optimum |
| 38 | ~5–6°C | Approaching late Eocene cooling |
| 35–36 | ~4°C | Lowest values in inset immediately before Antarctic glaciation |
| Event | Approximate age | Significance shown |
|---|---|---|
| PETM | ~56 Ma | Abrupt early Cenozoic warming |
| Eocene Optimum | ~52–50 Ma | Highest sustained warmth shown |
| Long-term Eocene cooling | ~50–35 Ma | Equivalent temperature declines by roughly 7–8°C |
| Antarctic Glaciation | ~34 Ma | Major Antarctic ice-sheet expansion |
| Antarctic Thawing | ~23 Ma | Temporary warming and/or ice retreat |
| Antarctic Reglaciation | ~14 Ma | Renewed Antarctic ice expansion |
| Rapid Glacial Cycles | Last few Ma | Repeated glacial-interglacial cycles |
| Abbreviation | Geological interval |
|---|---|
| Pal | Paleocene |
| Eo | Eocene |
| Ol | Oligocene |
| Mio | Miocene |
| Pli | Pliocene |
| Plt | Pleistocene |
Notes: The inset temperature values are approximate readings from the figure rather than direct observations. The main benthic delta-18-O record reflects a combination of deep-ocean temperature and global ice volume, so it should not be interpreted as a direct temperature curve throughout the entire 65-million-year interval.
Figure 8.2.1: Shared-Socioeconomic Pathway Carbon Dioxide Emissions Scenarios
Line graph showing historical and projected global carbon dioxide (CO₂) emissions from approximately 2005 to 2100 under five Shared Socioeconomic Pathway (SSP) scenarios. The horizontal axis represents year, and the vertical axis shows annual CO₂ emissions in billions of metric tons, ranging from approximately −20 billion tons to 140 billion tons per year.
All scenarios begin near 33–38 billion tons per year in the early 2000s and then diverge substantially through the twenty-first century. Positive values indicate net CO₂ emissions to the atmosphere, while negative values indicate net carbon removal from the atmosphere.
The SSP5-8.5 baseline scenario ("Fossil-fueled Development – Taking the Highway") shows the largest increase. Emissions rise from about 33 billion tons in 2005 to approximately 57 billion tons by 2030, 84 billion tons by 2050, 117 billion tons by 2070, and peak near 130 billion tons per year around 2080–2090. Emissions remain above 125 billion tons per year through 2100.
The SSP3-7.0 baseline scenario ("Regional Rivalry – A Rocky Road") shows continued growth but at a slower rate. Emissions increase from about 35 billion tons in 2005 to roughly 55 billion tons by 2030, 64 billion tons by 2050, 72 billion tons by 2070, and approximately 85 billion tons by 2100.
The SSP2-4.5 scenario ("Middle of the Road") rises slightly before declining. Emissions increase from about 38 billion tons in 2005 to approximately 44 billion tons by 2030–2040, then gradually fall to around 39 billion tons by 2060, 25 billion tons by 2080, and about 9 billion tons by 2100.
The SSP1-2.6 scenario ("Sustainability – Taking the Green Road") peaks early and declines substantially. Emissions rise slightly to approximately 38 billion tons around 2020, then decrease to about 26 billion tons by 2040, 10 billion tons by 2060, reach approximately 0 by the late 2070s, and become slightly negative by 2100 at around −8 billion tons per year.
The SSP1-1.9 scenario ("Sustainability – Taking the Green Road") shows the most aggressive emissions reductions. Emissions decline from approximately 35 billion tons in 2005 to about 18 billion tons by 2030, 1 billion ton by 2050, become negative shortly after 2050, and reach approximately −15 billion tons per year by 2100.
The graph illustrates that future emissions outcomes vary dramatically depending on socioeconomic development pathways and mitigation efforts. By 2100, the difference between the highest-emission and lowest-emission scenarios is approximately 145 billion tons of CO₂ per year.
Figure 8.2.2: Shared-Socioeconomic Pathway Carbon Dioxide Concentrations Scenarios
Line graph showing historical and projected atmospheric carbon dioxide (CO₂) concentrations from 2000 to 2100 under five Shared Socioeconomic Pathway (SSP) scenarios used in climate research. The horizontal axis represents year from 2000 to 2100, and the vertical axis shows atmospheric CO₂ concentration in parts per million (ppm), ranging from 300 ppm to 1200 ppm.
A historical line (green) shows CO₂ increasing from approximately 370 ppm in 2000 to about 395–400 ppm by 2014. After 2015, the graph branches into five future scenarios that diverge substantially over the twenty-first century.
All scenarios begin near 400 ppm around 2015–2020 and continue upward for at least several decades. The scenarios differ in the rate and magnitude of future emissions and resulting atmospheric CO₂ concentrations.
The SSP5-8.5 scenario (dark red) shows the most rapid increase. CO₂ rises from about 400 ppm in 2015 to approximately 560 ppm by 2050, 750 ppm by 2070, 1,000 ppm by 2090, and reaches roughly 1,130–1,140 ppm by 2100.
The SSP3-7.0 scenario (red) shows substantial growth but less than SSP5-8.5. CO₂ reaches approximately 540 ppm by 2050, 650 ppm by 2070, 780 ppm by 2090, and about 860–870 ppm by 2100.
The SSP2-4.5 scenario (orange) shows moderate growth. CO₂ increases to approximately 500 ppm by 2050, 560 ppm by 2070, and levels off near 600 ppm by 2100.
The SSP1-2.6 scenario (dark blue) rises more slowly, reaching about 470 ppm around 2050–2065, then gradually declining to approximately 445 ppm by 2100.
The SSP1-1.9 scenario (light blue) shows the strongest emissions reductions. CO₂ peaks near 440 ppm around 2040–2045 and then steadily declines to approximately 390–395 ppm by 2100, approaching current-day concentrations.
The figure demonstrates that future atmospheric CO₂ concentrations depend strongly on emissions pathways. By 2100, the difference between the highest and lowest scenarios exceeds 700 ppm, illustrating the large influence of future human activities on atmospheric composition.
Figure 8.2.3: Shared-Socioeconomic Pathway Methane Emissions Scenarios
Five colored lines on a white background track projected global methane emissions from 2005 to 2100. The horizontal axis shows year, and the vertical axis shows methane emissions in millions of metric tons per year, ranging from 0 to 800 million tons. Each line represents a different Shared Socioeconomic Pathway (SSP) scenario and is labeled near its endpoint on the right side of the figure.
The green SSP3-7.0 line rises steadily throughout the century, starting near 350 million tons in 2005 and reaching approximately 775 million tons by 2100, making it the highest trajectory shown. The purple SSP5-8.5 line also increases substantially, peaking near 645 million tons around the 2060s–2070s before declining to about 540 million tons by 2100.
The brown SSP2-4.5 line remains near current levels through the first half of the century and then gradually declines, ending near 255 million tons by 2100. Two lower trajectories show strong methane reductions: the orange SSP1-2.6 line declines from roughly 340 million tons in 2005 to about 120 million tons by 2100, while the blue SSP1-1.9 line falls from approximately 320 million tons to about 110 million tons by 2100, the lowest value shown.
The lines are close together near the beginning of the record but diverge widely after about 2030. By 2100, the gap between the highest pathway (SSP3-7.0) and the lowest pathway (SSP1-1.9) is approximately 665 million tons of methane per year.
The figure includes labels identifying the scenarios as:
- SSP3-7.0: Regional Rivalry – A Rocky Road
- SSP5-8.5: Fossil-fueled Development – Taking the Highway
- SSP2-4.5: Middle of the Road
- SSP1-2.6: Sustainability – Taking the Green Road
- SSP1-1.9: Sustainability – Taking the Green Road
Figure 8.2.4: Shared-Socioeconomic Pathway Temperature Increase Scenarios
Five colored lines on a white background show projected increases in global average temperature relative to the pre-industrial era (defined in the figure as approximately 1750). The horizontal axis shows years from 2005 to 2100, and the vertical axis shows temperature increase in degrees Celsius, ranging from 0°C to 5°C above pre-industrial levels.
All five lines begin near 0.9–1.0°C warming in 2005 and remain close together through about 2030. After that, the scenarios diverge substantially. Each line is labeled at its endpoint on the right side of the figure.
The purple SSP5-8.5 line ("Fossil-fueled Development – Taking the Highway") rises the fastest throughout the century. Warming reaches approximately 2.0°C by 2040, 3.0°C by 2060, 4.0°C by 2080, and slightly above 5.0°C by 2100, making it the highest trajectory shown.
The green SSP3-7.0 line ("Regional Rivalry – A Rocky Road") also increases steadily, reaching roughly 1.9°C by 2040, 2.6°C by 2060, 3.3°C by 2080, and approximately 4.1°C by 2100.
The brown SSP2-4.5 line ("Middle of the Road") shows moderate warming. Temperatures rise to approximately 1.8°C by 2040, 2.1°C by 2060, 2.5°C by 2080, and about 2.6°C by 2100.
The orange SSP1-2.6 line ("Sustainability – Taking the Green Road") increases more slowly. Warming reaches about 1.7°C by 2040, peaks near 1.8°C around 2070–2080, and then declines slightly to approximately 1.7–1.8°C by 2100.
The blue SSP1-1.9 line ("Sustainability – Taking the Green Road") shows the lowest warming. Temperatures rise to about 1.5–1.6°C around 2040–2050, then gradually decline to approximately 1.3–1.4°C by 2100.
The figure illustrates that future warming depends strongly on future emissions pathways. By 2100, projected warming ranges from approximately 1.35°C under SSP1-1.9 to slightly above 5°C under SSP5-8.5, a difference of about 3.7°C.
The title states: "Global average temperature increase relative to the pre-industrial era." A subtitle notes that the pre-industrial baseline is taken to be the year 1750.
Figure 8.2.5: Shared-Socioeconomic Pathway Sea Level Rise Scenarios
Five colored lines on a white background show projected global mean sea level change from 2020 to 2150 under five Shared Socioeconomic Pathway (SSP) scenarios. The horizontal axis shows year from 2020 to 2150, and the vertical axis shows sea level change in meters, ranging from approximately 0 to 1.8 meters. A legend on the right identifies the colored lines as SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. The legend indicates that the plotted values represent median projections; uncertainty ranges are available but are not displayed.
All five curves begin near 0.05 meters of sea level rise around 2020 and increase throughout the period. The scenarios remain close together through the first few decades but diverge progressively after mid-century.
The SSP1-1.9 line (lowest-emissions scenario) rises most slowly. Sea level reaches approximately 0.20 m by 2060, 0.38 m by 2100, and about 0.57 m by 2150.
The SSP1-2.6 line rises slightly faster, reaching approximately 0.23 m by 2060, 0.44 m by 2100, and about 0.68 m by 2150.
The SSP2-4.5 line shows intermediate growth, reaching roughly 0.27 m by 2060, 0.56 m by 2100, and approximately 0.92 m by 2150.
The SSP3-7.0 line rises more rapidly after 2050, reaching approximately 0.29 m by 2060, 0.68 m by 2100, and about 1.19 m by 2150.
The SSP5-8.5 line (highest-emissions scenario) shows the greatest increase. Sea level reaches approximately 0.31 m by 2060, 0.77 m by 2100, exceeds 1 meter around the 2120s, and reaches approximately 1.32 m by 2150.
The separation among scenarios becomes increasingly large after 2100. By 2150, the difference between the highest and lowest projections is approximately 0.75 meters.
The image also includes a checkbox labeled "Display Range" and a camera icon labeled "Take Snapshot," suggesting the figure may be part of an interactive visualization.