Invitational Seminars

The role of carbon cycle processes in global warming and how to stop it.

Imagine a world where the global temperature went up linearly with every increment of CO2 added to the atmosphere. The more CO₂ we add the warmer it gets. If we reduce emissions, warming slows but doesn’t stop: if we want to stop warming we have to stop emitting. That would be a very simple system, but remarkably the real world behaves a bit like this.

The relationship between warming and emissions is known as TCRE (the Transient Climate Response to cumulative carbon Emissions). It is not as simple as described above, but it works well enough to be a useful concept, providing a simple, scenario-independent relationship between cumulative CO2 emissions and global warming. The TCRE supports one of the most powerful and popular geophysical tools of climate science: the carbon budget. Our ability to quantify the emissions that are compatible with global warming targets is one of the biggest advances in our ability to inform climate mitigation policies. 

The concept of the TCRE relationship also brings interesting consequences for a world after we stop emitting CO₂. Once we stop emitting, the climate (in terms of global temperature) remains stable thereafter – there is no committed warming, or “warming in the pipeline”. We can even reverse global warming by removing CO2, and the same relationship holds as the world cools.

The old idea of committed warming, or “warming in the pipeline” was based on asking what would happen if we kept CO₂ levels constant in the atmosphere. But this is the wrong question – if we stop emitting CO₂ then natural carbon sinks will remove it and CO₂ levels drop. This means that we are not “committed” to ongoing warming after the point of zero emissions – hence it is known as the “Zero Emissions Commitment” or ZEC. 

Both TCRE and ZEC are critically dependent on how the world’s ecosystems – both on land and in the ocean – absorb carbon. In this seminar I will explain the science behind these concepts, their implications for carbon budgets and climate policy, and explore the “what next” questions as we are still trying to understand about the mechanisms behind TCRE and ZEC.

Rewriting the message: RNA regulation in cephalopods, aging vertebrates, and bacteria

Once a gene is transcribed, its message is not fixed. RNA can be edited at the sequence level, rearranged into distinct isoforms, or read with varying efficiency, and different branches of life emphasize these layers unequally.

In soft-bodied cephalopods, one such route is unusually pervasive: A-to-I RNA editing. By changing individual nucleotides in mature transcripts, editing can recode protein sequences, and it does so far more extensively here than in most animals. Squid, octopus, and cuttlefish therefore offer a striking system for asking which recoding events are tolerated, which may be shaped by selection, and whether neighboring editing sites are coupled into coordinated patterns along the same transcript.

A second eukaryotic route is alternative splicing. By combining exons differently, cells build distinct isoforms from one gene. During aging, splicing patterns shift across tissues and species, raising the question of which changes reflect general features of aging and which arise from tissue identity, changing cell composition, or transcriptomic noise.

Bacteria strike a different regulatory balance. With limited editing and no spliceosomal splicing, much of their post-transcriptional control acts as the message is read: short features near translation start sites, including leading codons and Shine-Dalgarno spacing, can strongly tune protein output.

Together, these systems show how RNA regulation expands the meaning of a gene, letting sequence, isoform choice, and translation efficiency shape biological output.